The new, PS3 version of Mass Effect 2 will look better than the original on Xbox 360 - that's because BioWare's using the Mass Effect 3 engine to power it.
“We actually created the engine for Mass Effect 3 and used that to make Mass Effect 2 PS3. So we took the content, the story and all of the other assets that made up Mass Effect 2 and we put it into the Mass Effect 3 engine. We’ve also gone ahead and made the experience much more solid on PS3. So for example the controls are geared towards the PS3 controller [although] you can switch it back to the old Xbox [layout] if you like. Other things like planet scanning have been improved; we’ve rolled up all of the patches; done a whole bunch of bug fixing.”