Integrated Amp Upgrade-itis hitting....

You might add the upper tier Yamahas to your list, maybe the A-S2100. They sound great, look great and have impeccable finish. 50 lbs of good ol' class AB MOSFET grunt. I have yet to hear an integrated amp that produces more accurate piano and string tones (to my ears of course). They are very neutral overall. 

The strength of the Parasound Halo is "body" in the midrange and upper bass. It makes for a very smooth listen but doesn't sacrifice much in detail. It can also drive just about any speaker with ease.

Tube integrateds will typically have a more 3D soundstage, but as mentioned, can become expensive in the long run for tube rollers. That said, if you've never owned a tube amp, you owe it to yourself to give some a try. I waited far too long to venture into an all tube amp. There's many great tube integrateds that are relatively affordable, especially in the used market. The Raven Audio Nighthawk is highly regarded, as is Prima Luna Prologue/Dialogue, Line Magnetic (various models) Cayin A88T, and Rogue Audio Cronus Magnum, just to name a few.

A very good, under-the-radar, but somewhat spartan amp is the hybrid tube/MOSFET Croft Phono Integrated. 

I have to chime in here you really need to go considerably higher in price to get an integrated amplifier which will beat the Musical Fidelity you have this is still an excellent integrated a little soft on the top and bottom compared to newer designs but still a nice piece.

We have a demo Plinius Hutongha which is a $5700 integrated that will beat the Musical Fidelity, and so would other similarly priced used or demo higher end integrated amplifiers, the Rogue Sphinx is an okay piece which in some ways would be better and in other way not.

The Marantz is a decent piece but again not a better product than what you have a lateral move at best.

Dave and Troy
Audio Doctor NJ

A lot thoughtful replies on here. I will agree with most that you will need the spend some cash to better that MF. Tubes are different, better at some things, not as good at others, and rubs rolling is a never ending process. Which, while fund, can get into more money than the amp. The Bryson integrated, whichever model you find be, can be fitted with an internal DAC and phono pre. If you want to get serious about vinyl I would recommend a separate phono pre that is adjustable for gain and load. The Emmaline Nighthawk is very nice and adjustable on the fly.

It sounds like you're looking for a "long term" center piece to build a system around. The MF you have now would be sufficient but  3 to 5 thousand will buy you an improvement that you could live with for several years. I don't think you'll see much of an improvement for much less cash.

No one has suggested the Moon neo 250i integrated or higher.... is there something wrong with Simaudio?  I am asking because beernut has transmitted his upgrade-itis...
I have had the Marantz 8400 for more than 5 years now.  It runs almost 24/7, it is dead silent, it has enough power, it is built like a tank, runs cool even when driven moderately loud,  and it sounds relax, laid-back, with some decent detail.  The volume control offers great contol unlike a nad, it adds decibels slowly with precision.  Before the marantz, I have had a nad 316, arcam alpha 8 (bi-amp combo), adcom 5300...
I paired the marantz with psb image t5 for some time; not a good combo at all.. it lacked dynamics and sound was too dark as if you had blankets on them.  I also have had the rega rs5 plugged-in; excellent combination, really really good... lively, clear, transparent midrange... I kept this for 5 years. Next, I have had totem hawks - good combination, but I think it does not bring the best midrange that the hawks are capable of, unless they are not capable of superb midrange.  I also have a pair of wharfedale Denton 80th.  Again, 2 laid-back components, not the best match...sounds a little too dark.
hence, me too... the upgrade-itis..  Moon Neo 250i anyone?

Thanks for the sage advice everyone. Seems I would need to drop some $$ to have a qualitative improvement over the MuFi at this point....Hmmm.