Play them in order. My thoughts on going from 1 to 2 to 3:
- Story gets progressively weaker.
- All characters get better APART from Ashley/Kaidan. They were the only characters that were better in ME1 and went downhill over 2 and 3. Other than that 2 and 3 have fantastic characters, even people like Vega.
- Combat gets better for the most part, although some of the charm is lost (overuse of biotic detonations, no holstering, maps designed for pure combat value at the expense of art/emotional impact, etc).
- Music becomes progressively more mainstream, although having said that I like all of the soundtracks.
- Story gets progressively weaker.
- All characters get better APART from Ashley/Kaidan. They were the only characters that were better in ME1 and went downhill over 2 and 3. Other than that 2 and 3 have fantastic characters, even people like Vega.
- Combat gets better for the most part, although some of the charm is lost (overuse of biotic detonations, no holstering, maps designed for pure combat value at the expense of art/emotional impact, etc).
- Music becomes progressively more mainstream, although having said that I like all of the soundtracks.