I'm using the Onkyo 606, which seems to be similar to the 663, and its does a fine job for me.
As far as comments about the system, I couldn't be happier. I got my surrounds installed this weekend and I still can't believe the performance I got for the price. Before I came here I was really considering just settling for the Polk Monitor 70's. Thank goodness I didn't, especially since I got the entire system for about the same price as 2Monitor 70's would have cost at some places. All I have to say is a big THANK YOU to the folks here at Audioholics for making people aware of EMP.