Yeah, I assume the creasing ball is little more than a software update to use the old pen/pounce hole to offer creasing too—alongside flexcut or regular cuts in jobs. Still cool! Maybe a little physical "beefing up" of things in the second tool slot on the head to add durability?
As far as I can tell, there's nothing new in the "sheet" department from the S2 to the S3? There is a small sheet fed stacker that's advertised with S1's, but the S2 already had a "sheet mode" that allowed you to feed (or even repeat on a roll) identical sheets with the same regmarks, sans barcode. Maybe I missed something else new?
But yeah, comparing apples to apples, the non-camera S2 and new non-camera S3 look identical aside from the crease wheel and Tron light. Like I told Ikarasu in another thread, I'd be looking for used or discounted S2's if I was in the market and wanted to save $, as there's effectively zero difference for general use, and the S2 is rock solid for those of us that depend on them.
That said, I'd be very tempted to buy an S3 if one of my S2's goes down, just because I've loved the S2's so much and from the looks of things, that quality continues with the S3.