The seats aren't leather. The center part is cloth and the outer part is a synthetic vinyl type material. I like it. It seems very durable.
As far as the gearing/towing, I've got the 3.21 and the tow package. Had I special ordered, I'd have gone with 3.73 and max tow, but I bought out of the showroom. That said, and though I've got no comparison, I don't find the 3.21 to be deficient at all. Of course I haven't towed anything yet, so I can't give you any insight there.
I live the Arctic. The ONLY negative I've seen so far is that the white trim on the steering wheel gets dirty easily, but that's nothing a little cleaner can't fix.
Do it. It's a great ride!
'12 JK Arctic Edition, a/k/a B.A. Baracus, a/k/a Bosco
Mods: AntennaX 13", 20% tinted front windows, Rugged Ridge XHD front bumper, Alpine SPS-610 (sound bar), Alpine SPR-60C (dash/tweeters), Olympic Safari mirrors (when doorless)