Pierrot and Colossous

Aside from the animations, is there any real difference between the two?

Essentially the same, as far as I can tell.

Oh yeah. They are completely the same. I read about it somewhere a while back. They're just appearance pleasers.

iirc, they're nx items you purchase from the item shop. So much for 'no need for NX to win', although that has never been true in the first place. This just backs it up.

No, the NX items are only if you want to dye them or get item shop-only character models. (And they don't contribute to stats, that's what the handles are for.) There is one other difference. In the marionette event, getting each of the two skills to rA(?) gets you a prefix title. The differences being the icon image and the stats of the prefix title. But after the event, the only difference is appearance and animations.

One more thing I noticed, their master titles are different. Colossus's master title is protection-oriented whereas the Pierrot's skills are offense-oriented.