Does it worth a upgrade to Dolby Atmos?

It seems Dolby Atmos is getting more steam recently. I have a 7.1 set up with Krell S-1000 processor and C-J multichannel amp. The sound quality is great. S-1000 doesn’t support anything beyond Dolby Digital. I am wondering if it worth to upgrade to Atmos processor (eg. Marantz AV770x, Anthem AVM60 used ). I don’t want to sacrifice theater sound quality ( I have dedicated 2-ch system for music listening. so I don’t care 2-ch performance). I have 4 ceiling spks and i can add 2 floor level surrounding spks w/o issue. That will give me 5.1.4. I have used Onkyo, Rotel, Krell Showcase and HTS before S-1000. HTS or S-1000 are big step up from Onkyo and Rotel. Will Marantz have same performance as S-1000 on home theater listening? I don’t want to spend over $2500 for the upgrade. Thank you.
For television viewing,  not worths it
Bluerays and Netflix , may be.
But you must be movie addick .

The audio quality may not be as good than your Krell
You are better with a very good 7.1 system than an averadge 5.1.4
  I am not sure the quality you will have with Marantz . Selling the Krell and adding 2500$ , can you  buy Acurus Muse for 5500$ . And their price ( Muse ) will be  higher in Febuary.

I do not know about your C-J multi amp Interconnect.
The Muse is all balanced interconnect.

Anthem AVM60 has a good acoustic room corrector : ARC

Auxinput ( a member )  could give you  a good idea about your questionning .

Thank you maxwave. C-J is single ended input. I used to have Theta Dreadnought  which is fully balanced. I found it is a overkill in my set up. I agree that It is better than C-J. But I am happy with C-J because it matches color with other C-Js in my 2-ch system. 
My Dolby Atmos system, one that uses a Marantz receiver and Triad speakers, sounds better to me than my previous system (all Meridian) that used older codecs. Your Krell processor is about the same age as my Meridian processor. I bought my Marantz/Triad system at a fraction of the cost of my Meridian system. Maybe my setup skills got better, but I attribute a lot of the improvement in sound to the newer technology available in my Marantz receiver. Not just movies, but sports and newer shows are available with Atmos and sound great. Streaming services such as Netflix, Amazon Prime, HBO Max and Disney+ all have shows with Atmos. The Mandalorian was a lot of fun to watch (and hear). I had a good experience going from an older "hi-fi" processor to a current "mid-fi" receiver with Atmos.
I prefer to watch to a clear , black and white , television ; rather than watching to a blur  , color TV .
But I am getting old, so it may just be  nostalgia .
I’m NOT a HT guy. That being said. Atmos is a great way to get great surround AND pretty good MUSIC sound out of pretty cheaply made speakers... I’ve heard the newer Macs.. I love um.. BUT I wouldn’t buy it.

I use Mac MX120, 121, Krell OLD 5.1 Excellent stereo, 3 speaker, SUB control and an OLD DAC that works GREAT...Class A pre amp.. Krell, just killer tech for its day and even NOW, when it comes to SQ,

3 speakers up front is a push for me...BUT done right.. in analog.. Actually is one of my favorite setups for music, MIXED for that type of speaker set up..Trinaural analog processor (SS too).. I like Macs over ALL the others. SSTs, or Marantz, there are a few more. Fisher and Bogden had tube analog units..VERY nice.. 60s (YUP).

Atmos.. BIG bang for the sound BUCK... If you choose better speakers, you don’t need the Atmos speakers. BUT there is a place, for close to the wall dipoles.

The only time a surround system REALLY impressed me.. 7.4.2 VMPS PRE Atmos setup with Mac Tube power amps for the mains and SS Mcintosh for the BASS and the rest of the surround duty.. VMPS used passive Subs...and love ALL the power you could throw at them. It was actually tuned by a Mcintosh (rep) and Brian C. of VMPS speakers. Weird speakers to begin with, BUT sure do sound good.. BIG BOOM, BOOM, for the time and could match the swarm idea!! 2010 or 11.

He upgraded just the processor to a MX151 or 160 (?) in 2014-15 for Atmos... I listened to that ALL friggin evening... 4 hours... 6 years ago..

50 year this summer, Me and Mcintosh. It’s been longer than my wife, met her 4 years after that...:-)

I originally came from an Krell HTS 7.1.  I currently use a slightly modified Krell S-1200.  I have also had a Krell S-1000 in my system.  There is definitely a difference between DVD audio and Bluray Audio.  The DVD audio (using old school compressed DD/DTS) is grainy and has loss of resolution when compared to bluray audio.  The S-1000 is very nice, but it is a downgrade from the HTS / S-1200.

The Marantz AV7704 / AV8805 are excellent processors.  I have also had them in my system for testing.  The AV8804 is excellent with strong bass/midbass and good impact on sound.  Marantz has excellent power supplies in their processors.  However, it does roll off the high frequencies some.  The Krell had much better high frequency response.  You just want to make sure you don't pair the Marantz with a warm amp because the sound may become too dull and you may lose visceral impact.

The Anthem is likely the best affordable modern solution if you are concerned about the rolled-off high frequencies of the Marantz.

It might not be an affordable option, but might suggesting trying to expand your budget for a Krell Foundation 4K.  It uses op amps and doesn't have the great sound of the discrete analog stages of the HTS/S1000/S1200, but it's excellent and I think it's going to be better sound quality than Anthem.  It is only a 7.1 processor.  One of the things I really like about Krell is that they use linear power supplies for everything, including the digital section.  Most processors will use linear power supply for analog, but will still use switching power supply for digital.

In my opinion, I would rather have a really excellent 5.1 system than a immersive 13 speaker Atmos system.  I've been in Atmos theaters and it's interesting to have all the sounds floating around everywhere (like the ceiling), but I can still hear the flaws in the speakers/amps they use.  It will likely be the same in your system if you really want the immersive experience, unless you spend a large amount of money on good speakers/amps.
I have also thought about upgrading to a processor with Atmos, but sound quality is highest priority. Unfortunately, there aren’t many very end processors available now that’s also good for 2 channel music. 
I have had Krell Foundation and S1200.  The S1200 sounds much better for music.  Recently replaced the S1200 with a Krell 707 with significant improvement in 2 channel sound quality.  HT sound is also really good, but doesn’t have the bells and whistles of new processors.  I will keep the 707 until there is processor that match its sound quality.
I have both the Krell HTS 7.1 and S1200U-3D and found the Krell "bubble" of sound is better at 5.1 then any ATMOS system I've reviewed, I also had the Marantz AV880x and Krell Foundation in my system and missed how the speakers vanished. If an excellent 5.1 or 7.1 system sounds amazing, why would anyone want to change to ATMOS unless their attempting to buy cheap equipment or looking at becoming a hugh movie theater where the goal is different. This reminds me when everyone needed 7.1 to feel satisfied, but it was only needed with large rooms.  I looked at getting the Krell 707, but when it jumped from $18,000 before release to over $32,000, I got off the audiophile bandwagon.
Beyond yes! Atmos is to home cinema what 5.1 was to Dolby Prologic , the upmixers will even take a standard TV show and breath new life into the audio. No 5.1 processor no matter it's pedigree will outmatch a properly setup native 7.1.4 or 5.1.4 playback system.
Do it!
ATMOS is the first 3 dimensional playback format that has music creators excited.  There is a ton of work going to remix records into the ATMOS format.   For film, ATMOS makes perfect sense to create motion, create the environment and space.  For music, it is a creative opportunity for composers and mixers alike.  I've heard quite a few mixes in ATMOS that were mind bending. Abbey Road remixed in ATMOS by Giles Martin is like hearing it for the first time all over again- so exciting!   Amazing experience if played back on a proper discrete channel ATMOS rig (not a sound bar that says it can do ATMOS). 
Where can I get Atmos music downloads ?

Tidal has some , I am a subscriber but I would need eArc feature on my processor.
I do not have a BlueRay player.I have Apple TV 4K.
I’ve used receivers as prepro’s since the begining dolby surround mid 80’s. I have never seen or heard a reason to do it any other way.
My 7.1.4 system transports me with the right soundtrack, even that Atmos that AppleTV sends to my Denon. You got me thinking maybe Tennet tonight 

i have a seven speaker diy build from HT Guide for the surfounds and mains, little SVS satilites for the Atmos channels.

def worth it when done right

In terms of 2-channel stereo listening, which preamp mode has a better sound, Krell HTS or S1200U? Thanks in advance

Brass2002, to reply to your question one year later... :) Have had the HTS 7.1 for several years now and it is excellent. Very recently acquired an S1200U-3D and has only been tested, not fully integrated in my system. The analog sound is quite different from the HTS, but far superior I believe. I used a separate Krell 280p (with HT bypass) for stereo, which has a more detailed and controlled sound than the somewhat mushy HTS analog preamp. The HTS analog sounds good and 'warm' but lacks detail compared to newer / more sophisticated options. The S1200 in first impressions even beats the 280p for stereo. A more modern and sophisticated sound, with more detail. Hope that helps. As for movies/surround (for which I used Oppo analog output into HTS) it does not matter that much honestly; the HTS is excellent there as well. As someone else said, the Krell bubble is the best and far superior to anything from Marantz or Yamaha that I have tried. Whenever I watch a movie/series, I am always impressed by the sound quality and immersion, even after many years with this system.