I really enjoyed this movie. It started off a little slow to me, and I thought it took too long to get to the actual "Iron Man" action, but the backstory was interesting enough so that that wasn't bothersome. I look forward to the sequel!
I found this movie to be a bit uneven -- on the one hand, it certainly made for a pleasant couple of hours on a Saturday afternoon, but on the other hand, it wasn't what I would call memorable or commendable. I also wasn't sure what genre it was intended to occupy -- it wasn't funny enough to be a comedy, nor compelling enough to be a drama. My advice would be to watch it if ever it comes on TV or a premium channel to which you currently subscribe, but not to go out and pay money for it.