Sorry, I did mention I was getting one, I thought I did anyway. Between the two, the practical side of my brain prefers the 3400 because it runs so cool that I won't really need to as an external fan. The irrational side eventually won because I was tempted to try Atmos, without giving up my SBL and SBR. Now my HT room is only 12X18.5X7.5. It is jammed back with speakers and 5 subs as it is, so I haven't figure out where to put the Atmos speakers yet.
All ideas are welcome.. I can tell you it isn't easy to admit not being able to tell much of a difference between the $560 (US) X3400H and the CA/A21. it is getting ridiculous, but thankfully I can still easily tell a difference between XT32, off, flat, reference, and between any of my speakers. Sometimes i thought I could even tell the difference between my external DACs too. By the way, before i return it, I did try the 3400's internal DAC using HDMI to my MacBook pro and love the sound quality. I really feel bad about returning it, and I hope whoever getting it will get a decent discount.