It's neither of these to me. It has the benefit of introducing us to real-world Transformers, so a lot of people view it with rose-colored glasses. But as a movie.... yeeesh. It's bad. Really bad.
How has no one mentioned the battle cry "Michael Bay raped my childhood!" yet? That was probably in most of the movie threads around here for a while after the designs began leaking.
This. Honestly, I tried watching it the other day, and I find every single one of the sequels more watchable. I think the series has gotten better as time has gone on. Much better.