I approached this film in two minds. I'd read a lot about its inconsistencies and historical distortions, and even suggestions of homophobia and racism.
First time I watched 300, I didn't really enjoy it. This can be put down to watching it on a 15" poor quality TV.
I decided to give it a second go - watching it in high definition on a 42", and the difference was staggering. I'm now very much a fan.
Regarding the historical mistruths - these are easily explained by it being based on a comic book and not history.
300 has little to no plot, but it is a pure, visually stunning, adrenaline filled, testosterone pumped dream (or nightmare depending on your tastes).
Taken for what it is (a comic book brought to life), it's hard to take negative claims against it seriously, because the film itself is not serious outside of its own narrow origins.
If you are looking for a film with depth and meaning, please avoid this film at all costs. If you are looking for an exciting, visually impressive comic book action film, then walk this way.