The AX1 was a true star. It will be hard to replace in many respects, although the processing can be bettered by almost any mid-range AV amp or receiver these days, such is the speed of technological improvement in this area.
The amplifier stages are harder to replace, though. You would still be looking at a flagship class player to deliver anything like the muscle and grace of this amp. Look at or near the top of Denon, Pioneer, Onkyo, Arcsam or Yamaha's range to find a replacement.
Perhaps someone who's made the jump from the AX1 to something more current could be more informative.
