MA9000 VS MA8900

I've heard great things about Pass integrated amps or their amps in general. I've never heard any Pass gears before as we do not have any Pass dealer in my area but I'll be psyched to be able to hear one some day.

I would also highly consider the following integrated amps : 
* Audio Research Foundation integrated.
* Naim Unity Nova (streamer / DAC / integrated amp all in one chassis). 
* Devialet (any models according to your budget). Naim also makes a pure analog integrated amp some at much higher price points than the Unity Nova.
* Classe Sigma 2200i stereo integrated amp. This integrated amp will digitize its analog inputs. It is a direct digital amplifier. No DAC. 
* Rega Osiris integrated amp. 

@caphill
I auditioned the Naim Unity Star yesterday, paired with a Focal Kanta, and left very impressed. It looks so sleek as well.
My needs are quite different, but for someone looking to have a single box with everything in it (including a streamer) & getting off the gear merry go round, its the best around.

Devialet - I have auditioned this, good sound but I prefer a more old school approach & look., also the thing I have against them, their product cycles are very short, i don’t want to be in a position of putting down 10 grand and finding in a year that my Amp is an older model., resale value takes a huge hit.

Rega Osiris - I did audition this, paired with a YG acoustics Carmel & a Rega Planar 10, Maybe it was not set up well, but I was a bit underwhelmed, considering the price point at work.,

Classe Sigma - I have been hearing great things, I need to audition it, but how is the support & warrant now that they have had a management change.

Audio Research - I haven’t heard any of their gear, definitely need to audition this.

@mtrot thanks for your comment & info in the thread posted.

Mavvrik, 
It all comes down to system synergy after all. You will need to demo different integrated amps with your speakers in your own listening room if you can take home demo that would be ideal, and go from there. Pick the one you think sounds best on your speakers. 

Re: Naim Unity, the Unity Nova is a step up sonically from the Unity Star. The Nova is Naim's top of line model in its Unity series. 
Speaking of Naim, I had a chance to hear the Naim Statement gears at my local dealer earlier this year. Naim Sttement consists of a linestage analog stereo preamp and monoblock amps. They retail for $270k. $90k for the preamp and $180k for the monoblock amps.
They sounded absolutely phenomenal. The best sounding gears I've ever heard. They were paired with the Wilson Audio Alexx speakers and those DCS Vivaldi full four stacks (Vivaldi master clock, Vivaldi upsampler, Vivaldi DAC, Vivaldi CD/SACD transport served as digital front end source components.

Audio Research Foundation series is entry level offerings from Audio Research. They are wonderful sounding gears. 

I’m late to the party here, but wanted to add my observations about the MA8900.  I bought one a year or so ago based upon reviews and frankly for the appearance.  I was so excited to bring it home and enjoy it.  I pulled out my existing Hegel h360 and turned it on.  To my disappointment, It sounded really dull and lifeless and I attributed that to a need to break in.  So I left it on playing in the background for a couple of days.  After waiting, it still sounded flat and lifeless to me.  It was a very noticeable difference. Long story short, I never took to the sound and returned it.  When I put the Hegel back in, the music returned.  To MY EARS, the Hegel sounds much more refined and natural.  It really broke my heart because the Mac looks fantastic and I believe it’s a well-made product, but I just didn’t care for the sound. I’ve since upgraded to the h390, and it’s just fantastic and a significant upgrade to the h360.  But we all listen with our eyes as well as our ears, and I understand that all of that plays into our enjoyment of our systems.  The Hegel certainly doesn’t look as nice as a Mac and I doubt it will last as long or retain its value as well. 
Like everything else, it’s all a matter of personal preference.  My suggestion is to disregard professional reviews or the opinions you read on forums like this (including mine).   Listen for yourself.