IYO. I think GL is as good as those. Not in the league of Dark Knight, X-men 2 or STM, though. But definitely a great intro movie. As good as Iron Man, X-men, Spider-man...
The first hour is amazing. The movie has some pacing problems in the last half hour but its still very good. So does Spider-man and Begins which are also filled with cheesiness, bad villains(Scarecrow)... Hector Hammond is much more developed than Scarecrow in BB. Scarecrow was just a thug in the movie. That's all.
GL Definitely DESERVES at least a 7,5. The thing is, Hal Jordan DOES NOT have an origin that is as good as those characters you mentioned. It is not as good as Superman`s, Batman or Spider-man. The best GL stories are the ones after that. My favorite stories are his descent into Darkness, destruction of Coast City, the corps and Kyle Rayner, who is my favorite GL. This movie was just a taste and that's why It should get a sequel. It left me wanting more. More exploration of Alien worlds, more interaction with GL`s. You can't do that in this movie without losing focus that this WAS Hal Jordan`s story and, imo, it's much better, more fun, than BOTH his origin stories in the comics.