no way would i use alo as an amp for iems unless they are really hard to drive
but with headphones alo mk3 is top of the line with the best ever bass boost tunes that has been ever created on headfi, unlike all the other gimmick bass boosters in other amps. It has a huge sound stage with amazing sound quality signature. This is the only portable amp I tried that makes planar headphones sound as if driven from a desktop amp
i really wish there will be a new rx mk amp update with the same bass boost implementation coming as this is the best alo portable amp with that gorgeous bass boost, I just can not know why ALO moved that bass boost from their new amps
I haven't tried the Rx MK3 but I have had a number of other Alo amps, which are great. For me the only portable I've tried which tops them is the Vorzuge Vorzamp Duo. Incredible bass and treble switches, compact, and powerful enough to drive hungry cans. I use it every day stacked with my A&K ct10.