I recently went through this and did some homework.

It really depends what scene you are into.

I went with 57mk2 purely because i'm a scratch DJ and the layout and workflow seems a little more suited to that, if i were a club DJ would've probably gone the 62 since it has hardware effects built-in, the loops area seems a little more accessible and visible on the 62 also which would help in the club scene.

In saying that the 57 still has hardware controls to access serato effects which suffice for the few effects i use, it has a FlexFX loop also for external units. As a scratcher it is nice to have the fader contours etc closer by, i don't beleive the 62 has channel swap either, i could be wrong though.

by the way i f*kn love the 57mk2, was worth the $ in my opinion.

Senato DJ rane ttm 57 mk2 combination worked flawless on my Mac 2ms usb buffer I had the rane 62 an d 62z and they're excellent but the sound quality is better on the 57mk2 it sounds like the original 57 just more stronger 57 mk2 all the way