A truly superb game even though it might not be best classified as an RPG.
I've played countless RPG games through the years as well as many of the more open-ended style games that have both a main quest and many side missions. Honestly, in ME2 one finds a fairly straightforward presentation in this regard as it is not often one finds missions that are too far off the beaten path. In some ways, this makes the game feel a bit linear but the scope of these missions makes up for this in many ways. Solid voice acting, dialogue trees, and mission story lines are fulfilling and generally worth the steps they take. Too, they add valuable character development even though at the latter portions of the game I found myself more interested in the climax rather than doing more side missions. Things were just getting too exciting to want to play out through some random character problem.
Looking at the overall art direction of the game, ME2 certainly stands out. It is serious and a thoroughly well developed space drama. It does not feel campy or over done and the entirety of the game comes across quite well done graphically, musically, etc. What's more, the last quarter of the game or so things really pick up and the game just gets incredibly interesting and is hard to put down. That said, ME2 is quite well paced from the story end of things despite having to spend some extra grinding time scanning planets to find stuff to upgrade. That, honestly, is probably my biggest quibble with this one.
ME2 was a refreshing addition to my gaming this year. I'm glad I played it and it is such that anyone this generation should take the time to thoroughly play it through. Just know that right about that time you start getting a little bored, that's when things really get going in a frantic pace to the end. Well done BioWare. Well done!