Are you using it as stand alone or a pre-pro?
I ordered an RX-V663 a couple days ago and after further research on this site and another the online retailer that I ordered it from has been out of stock and shipping the RX-V665 as a replacement even though it shows the RX-V663 in stock on their site...
So with that said. Why not look at the 665 or if you're using it as a stand alone unit, the 765?
If the Co. I ordered it from sends me a 665 as a replacement it's fine with me as I'll be using mine as a pre-pro so the amp section is of no concern to me, but if you're using it as a stand alone unit you may want to look at the 765 for the better amp section, even though it's not huge between the two.
I guess my point is... From what I have been told you cannot find the RX-V663 anymore and any online retailer selling them right now is just selling vaporware and I have a sneaky suspicion that come Mon. I'll see an email telling me they are out of stock on the 663 and that they shipped a 665 as a replacement.