I did play the Beta, and I will gladly warn you that yes, it's really too different.  Whereas Smash has you beating people up to increase their aerodynamics, PSASBR has it that no amount of attacking opponents will actually lead to their destruction.  All it does is fill up your bar which then allows you to use a super-move which IS capable of scoring kills.  When you connect with those attacks, your foes simply disappear only to respawn and continue the battle.  One of the largest problems, though, is that there is NO period of invulnerability when you spawn...I only played a few matches, but found myself spawn-killed rather quickly.

The controls are also...unclear.  There are three attack buttons (circle, triangle, and square), all of which seem to do different attacks if you're on the ground or airborn, and possibly also in combination with analog stick direction.  But for my money, figuring out what does what is MUCH harder than in Smash.

I had been looking forward to PSASBR, but after playing the Beta, I lost all interest and cancelled my pre-order.  If you're a Smash fan, you'll be hard pressed to find something to like about this game.

@IAmNotWill Impressions haven't been overwhelmingly promising across the board, unfortunately.  Destructiod seemed to like it somewhat, but IGN and Gametrailers weren't hot on it at all.  I remember an editor from Gametrailers saying "it puts itself on a flawed foundation just to be different from Smash Bros."  Plus there's discrepencies as to what it's trying to appeal itself to.  It seems too complicated to be a good party fighter like Smash, but there isn't a lot of stuff for the core fighting gamers either.  Also, I've heard of some big balancing issues, but those could easily be fixed, and its probably why it got delayed.

Do you have any links? I couldn't find too many impressions from the larger game sites.

I really enjoy it as a fighting gamer. The online is fine, but is still buggy. I play Raiden and have been randomly teleported into the battle ball several times without dashing or jumping into it and a lot of times I can't find a game, sort of like in Marvel 3.
The diversity of skill is nice, but the ranking is a little daffy. I can be playing in a 2v2 and still be demoted if I end up losing that game. Now, the roster isn't fully used like in most fighters; well, I at least haven't fought every character online yet.
Now, the standard arcade stick layout is a bit messy, they should have had Clowckw0rk make that. I was surprised they made throwing a possibility on stick without my having to shift from DP to RS.
So far, with the current roster and general accessibility to everyone I give it an 8/10.