There should be no problem with the IPS-1 being paired with the 990, but an extra 25W isn't likely to be audible, much less significant.

The Emotiva amps are built overseas, and as such will cost less per watt than the US-made Outlaw amps. The Emo amps have been generally well received. Their processors get more publicity, as you've noticed, which may be for bettter or for worse (the LMC-1's history is scattered across several forums and includes a fair bit of my involvement, and there have been some issues that have made me pretty uncomfortable).

My suspicion is that the two routes would be very comparable. That doesn't help much, I know.