I don't know about the PS3 version but my friend has all of them on 360 and I have them all on PC. The Xbox versions are alright but you just can't beat the smooth fluid frames and silky graphics that you get on PC, and you get to use the Xbox/windows controller too.
It all comes down to personal preference, a game can be made or broken based purely on how the controller feels in your hand, id base the decision on that alone, because this late in this generations life cycle there is very little difference between the two in graphics and performance.
I'm sorry... but anything with Ubi's DRM doesn't deserver a win.
As for the OP, they are essentially the same on both consoles, if you are getting the newer games (Brotherhood onwards) then you may want to choose the console with friends who play so you are able to play together.
PC rules all over them.u cannot find the smooth gameplay of PC in anywhere.but for those console,i will definitely give my opiniom to PS3.the graphics are little bit in ps3 since it uses bluray HD disc.but u will not be able to see the difference.i have both ps3 and xbox360 and also a Gaming pc.in my opinion get the ps3 version,it will give u faster frame rates than xbox 360.texture quality and lightning is better in ps3 and controller is also good.
PC blows those consoles in dust with dynamic lighting,anti aliasing,texture etc.my pc specs is intel i5-2500k,gtx 670,12GB RAM,alienware 3D monitor
Theres been a few comparisons for graphics, and the general consensus is that Xbox usually beats PS3(the differences are minute, its usually just shading). The controls, on the other hand, are slightly better on PS3. I played Assassin's Creed 2 on PS3, and Brotherhood and Revalations on Xbox. I prefer the xbox version, but not by much.
That being said, PC > Console version. I'll be getting Assassin's Creed 3 on PC when it comes out(whenever that may be, they keep delaying it)