This was my first experience with Mass Effect,and I have to say I love this game. I've played it through 5 or 6 times and although some of it is repetitive and a tiny bit boring the over all game play and story makes up for all that.
The game gets better the more you play it, going back and playing me2 and now me1 (thanks to the mass effect trilogy) just brings everything together.
As for the multiplayer portion of the game (ps if you want 100% galactic readiness multiplayer is the easiest way to go). Anybody that's ever played an MMO knows that there is a good time/bad time to play depending on if you want to listen to all the people with mics. The overall play for the multiplayer is just as good as the single player portion without an actual story line, and if your feeling up to kicking cerebus or reaper butt you get to choose.
This is one of the best games i've played in a while.