I had the standard micro. I never had the gain past 11 oclock even with a jan 5751 in Iit (which was a huge improvement). I found the mp3 input too finnicky for practical use...but it was great for hooking up an mp3 player to break in speakers.
They are fun amps, but yeah...needs a "real" speaker/cab.
I havent played the micro dark. I wouldnt need the loop, but its my understanding the headphone out is cab sim, which is a plus. Ive yet to hear a decent 70s rock sound out of one... It seems gainier than the standard micro terror. Id like to try one to see for myself.