I have had an X5 for almost five years now. It is simply incredible, and has tremendous dynamics. My mains are Hales Rev 3's, and back to back with both an Aragon and an Adcom, the X5 simply puts them to sleep.
I've had the amp in once for service. I had it back in two days, no questions asked. The service is simply superb, and when I've asked, Nelson Pass answers the questions himself.
Without reservation...get the X5.