I had a C2.2 last year. I sold it to try the NFB-10SE with the LCD2v2's (didnt try them on C2.2).
As far as i know the C2.2 is simply the newest and most improved version with the most power output of the family other than the C2-SA.
The C2.2 was a great amp and i would not hesitate to buy one again.
However i got lucky and snagged a C2-SA From the classifieds here. The NFB-10SE is now sold and i am keeping the C2-SA forever, i love it that much.
I really lucked out as this amp just has gobs of power for low impedance cans and could probably run even the Hifiman HE-6. it is not listed on the site, anymore, not even in discontinued, but here is the page found via google.
this amp is different as it is a diamond differential amp. it puts out 6W of power into my lcd2's!
the synergy is great with them. This amp was designed specifically with planars in mind.
kingwa's description is below;
The C-2SA applies diamond differential amp. It has its particular musical sound flavors which can't be found in any other amp design. Its sound a bit of softness, warm and relaxed, allows users to pleasantly listening for a long time. Its sound is on the musical side but the detail and dynamics are still reproduced.
25 ohm: 6000MW
Edited by darren700 - 6/2/12 at 8:59pm
100 ohm: 3000MW
300 ohm: 1000MW