So, Sony Smash Bros.:
The game does not come with a voucher code to download the Vita version. Instead, when you put the disc in the PS3, three different icons come up- The game, its digital manual, and extras, which takes you to the PSN Store and lets you download the Vita version. You can't download the game until you redeem the online pass and it ties it to one PS3/Vita, so in other words, no game-sharing is going to happen from this.
Played the game on Vita first, going through Nariko's tutorials and did the arcade/story mode. The game play is still simplistic like other party fighters, but does offer combos and juggles like a "normal" fighting game.
Got online on PS3 in a ranked match against three Raidens at levels 68-75. Destroyed them with a three-hit kill level one super shot...TWICE.
All-Stars is a fun game once you find a character you like and get the game play down. I'd definitely recommend doing the tutorials to get your character's unique abilities and combos down before jumping online.
Definitely still think the game lacks style compared to Smash, but it's still pretty good. I think I prefer the control scheme on the Vita version over the PS3 version.
It's hard to tell if the PS3 version looks any better than the Vita version. Both games pretty much look the same from what I can tell. It's not the most visually-impressive title out there, but the game stays locked at 60 FPS and the netcode is great.