I too am considering the Pass X series, I presently own a pair of Mac 501's, I have owned a Mac amp since 1978, no other, my fear is if I change I may not like a different amp due to I am so used to the Mac sound. Another problem is yes you can go to a showroom and listen to different amps, however it may not sound as good in your system. I live in Wichita KS and there are absolutely "zero" highend establishments inside of a 200 mile radius, most places in KC will not hear of taking a piece home for a brief audition. So what do you do? I have considered moving up to the MC-1201, I was trying to wait to see if Mac will be announcing a new line of amps anytime soon, does anyone out there have any updates concerning Mac upgrades?