Slot me into the "good, but not great or especially memorable" camp. Its light and breezy and fun, but its so damn derivative. It goes everywhere you expect it to, and not in new or exciting ways. The direction is really poor, and the editing was rather shoddy too. The characters all feel so one dimensional, Stark included. And I am about the biggest RDJ fanboy you'll find, but I honestly dont think his performance was as charasmatic and engaging as its being made out to be. I felt his similar performance in KKBB was leagues better, and worth the price of admission for that film. Back to some final positives: the effects were great, there was some great humor, and RDJ's performance, while not the second coming as previously mentioned, is still the reason to see the movie. Ill see the sequel for sure, but its not something Ill be biting my nails in anticipation for.
Since this is the internet, and comparisons are what we do, Id slot this into the middle tier of superhero flicks. It shits all over the X3's, Punisher's, Fantastic Fours, and the Superman Returns' of the world, but I don't think it holds a candle to S-M2, BB, or even Sin City. For me, this is basically on the level of S-M1 and X2.