I would like to ask you, which one should I ideally choose. I do not need phantom power,because I will not use mic at all. I do not think that knobs on the upper side are very big plus too.

My probably main concern is, if MK II has USB 2.0 or the 1.1 and is just "USB 2.0" compatible. If those are both 1.1, I would personally choose older version because it is about 1/3 cheaper.

I will be using it for recording guitars in Reaper 0,99+free VSTs and I have experience with MK 1 and it was ok, with several VSTs with no slowdowns. Only when I tried SIR+IRs I noticed strange delay (maybe only because the verb, not sure).

Also I am not sure about guitar inputs. Both units have one guitar imput right?

Rig is C2Q6600, 8GB RAM.

Thanks for any help to the right direction.
Ibanez RG570EX, Dunlop 8-38 E Standard, B.C. Rich Warbeast WMD, Dunlop 9-42 E Standard, Boss MT2, Sencor 30W, Planet Waves, Fast Track MkII. Dunlop Jazz III, Stubby