I'd go with the Pass any day. 400 wpc for a home theater sounds like overkill to me, unless your room actually is a theater. Also, can your electrical system deliver that much power?
Amp Advice for newbie
Buying Nautilus 802's and 804's with HTM1 center. What difference will I get from say a higher quality amp with lower power like a Pass X5 versus say a higher power amp like a Sunfire 400W per channel? Getting much advice, do I want more wpc at good quality or lower wpc at better quality? Trying to manage my expectations and budget.