Suggestions for upgrading amps in my home theater system

How are your speakers set up?  I have a 5.1 system for home theater and have been very happy.  That said, with a 5.1 you have 2 main fronts, a center and 2 rears with a sub.  If I had an amp that I loved the sound of I would put this on your mains and worry about the surrounds from "other" amplification.  This also gives me the option of playing in stereo mode with speakers and a amp that I love the sound.  That is what I did.  Is it perfect, I don't know, it works for me.  I would be tempted to purchase 1 of the Anthem 525, play through your mains and compare to the Moon.  If Anthem wins, sell the Moon and proceed.  If Moon wins, you have to purchase 2 more channels and perhaps go with the Anthem 225. 

I know that with my set up I run in everything from 5.1 to 2.1 to just 2 channel.  You will notice, based on the way things are recorded.  I run a fair amount of turntable and cd on my mains and trying to run anything besides stereo mode, sounds wrong to me.  To me the center comes into play when you are running things beyond the 2 channel config. and, to me, acts more as part of the surround.  I'm just saying wait on selling the Sim amp until you absolutely know you're headed in the right direction.  Sorry, I've taken too many trips in the wrong direction and or given things away and just wanted to hit a untouchable rewind button.  I'm just saying what I would do, what works for me and some mistakes I've made.  Good luck.