The only significant difference, which boils down to personal preference, is the lighting in the two games. DF notes that the PS3 version's lighting is generally brighter than the 360 game, though not necessarily improved from a technical standpoint. The article also examines the effectiveness of the PS3's "Genesis" comic intro, as opposed to actually playing the original Mass Effect on 360.
In the end, if you just have to own the most technically impressive version, DF suggests you choose ... the PC version, of course.
Source: Eurogamer
Via:Joystiq