As an owner of both Mass Effect 1 and 2, I have to say that ME3 was fun; most of the time. I also feel that Bioware and EA let their wallets go to their heads since the most critical aspects of the story can be considered one of the most poorly executed as I have ever seen in games.
This is a buyer beware. If you want a good story, that's sort of iffy. If you want lots of fun blowing stuff to pieces, then it's awesome.