I will say nothing about the other amps that you mention but I will speak about the X 350. I have had several customers purchase X amps from me and then sell them to get something else as we in Audioland have a tendency to bounce back and forth. The interesting thing is how many of the previous Pass owners have gone back. Everytime I sell my X 600 demo's off the floor I wait with bated breath to get my next pair. Realize I carry some extraordinary amps; the Nemo's, Joule Electra mono blocks (awesome amps), Red Rose mono blocks (very seductive), and Aronov mono blocks. I also have the Alchemist and the Bel Canto's bridged. The Pass just have a presence about them that seeps into your being. Are any of the amps mentioned above better? They are all very good and that is where personal flavor and preference comes to play. Realize the three amps that you are considering are very different from each other.