MK2 because it's challenging and fun

I'd go for MK2. MK1 on SNES was not fun because of the laggy controls. MK3 and UMK3, while the graphics and sounds are decent, have terrible gameplay. Mk2's gameplay wasn't that great to start with (in the arcade) and the SNES version is very different, but it is fun.

Good for specials and fatalities (don't need to hold block in many situations) but bad for everything else. Plus snes has the easiest infinite of all time.

If you like fast combos and lots of characters, get MK3 or Ultimate MK3.

If you like slow broken cheap fighting, get MK2.

We're talking SNES here. Which means if you like Fast broken cheap fighting get MK3 or UMK3.

If you like slow broken cheap fighting that looks a little cooler, get MK2.

Both suck so it comes down to which is the lesser of 2 evils.

MK1: Wouldn't reccomend it for SNES. Two words:NO BLOOD!!
MK2: Pretty good. One of the best MK games. On SNES there is weird sound, but it is a lot like the arcade version.

Although my favorite games in the MK series are MK3/UMK3/MKT, I have not played MK3 or UMK3 for SNES yet, so I'd choose Mortal Kombat II.