In my experience, the SKS is difficult to scope reliably, and aftermarket mags don't seem to work all that well, so the SKS is at its best if you want a strictly-iron-sighted, 10-round-fixed-magazine rifle.
The Mini Thirty comes with scope rings and bases, has nicer fit and finish, and is smaller and lighter, with the added benefit of detachable mags. On the downside, it is undoubtedly less rugged. Accuracy is probably comparable to the SKS.
If you want a detachable magazine carbine that can mount optics and uses detachable magazines, you could also look at a Saiga or an AK with the built-in optics rail.