Marvel vs Capcom and King of Fighters. Look at those games, then look at SSB. Those (MvC and KoF) are normal fighting games with health bars, much like Street Fighter, with a bunch of different characters from different places (Mash-up if you will). SSB is more of a party based, ring-out fighting game (or brawler). Going to a shallow point, LOOK at the games! SSB has the 3D models and scenes in a 2D plane, childish cuteness all over the place, stages based on games with a certain feel to them (oh, and one character that is 2 dimensional Mr Game and Watch). KoF and MvC are spritebased, is 2D all the way through, has a more raw feel to the stages (set to correspond with the characters).
Yeah, enough about KoF and MvC versus SSB.
Now look at SSB and PlayStation All Stars Battle Royale. Going the shallow route once again, and hey, looks are the first impressions: 3D models and scenes in a 2D plane, the same cuteness (in lack of a better word of phrase to describe it) mixed with character models looking more like their original characters (nathan drake), but still fitted to match the rest of the graphics in some cases (fat princess for example). Also, there's one 2D character: Parappa. Themed stages (like it should be) that has the same feel to them as the ones in SSB, with the exeption that they mix two games for each stage (I like that idea a lot!). However, the looks of the stages and the feel of the stages graphically is the same as SSB.
For this point, I want you to see these two images, one from SSB Melee, and the other one from PSASBR:
Yes there are clear differences and all, but the feel of it all, the "cuteness" that I can't describe better...
Another point is the "final smash" attack? Was it called that? I'm not that good with names. When you've filled your gauge, you get this super power killing everything in a wink of an eye. Very much like the "smash"-orb thingy in SSB Brawl, not how you get it but how it works when you use it. Also, visually it has many similarities.
Like many have pointed out before me, many of the moves (again, visually at least) looks very similar to SSB, fall saves and whatever it's called. I must say though, that there's only so many moves to choose from, and I won't blame them for it.
Bottom line of this though: There are MANY similarities, much more similar than KoF and MvC are to SSB. Technical and visual similarities.
I DON'T BLAME THEM! This is a party brawler fighter thingy. mashing up awesome looking 3D models, so you have to make some changes and make them fit together. Just like SSB does, and I think it's fine!
I want this game! I think it looks AWESOME! The not-health-bar in PSASBR works differently than the not-health-bar in SSB, for better or for worse, I'll have to play it to decide. Hopefully that can be changed, just like in SSB (different modes).
Is it a rip-off? well.. kinda, a little bit in my eyes. They've said it themselves that they've "inspired" by SSB. Fair enough, they wouldn't say anything other than that. I accept it! Still looks awesome.
However, it's the "There are no similarities other than there are different characters from different IPs brawling"-comments that I don't accept. All those that scream at the top of their lungs that there are no similarities. Yes there are! Oh well, I'm getting tired.
Ultra TL;DR:
It IS an awesome rip-off (couldn't probably be done better at all). And I don't hate Sony for it (I'm looking forward to it!), I hate those who denies it.