I don't know about everywhere else, but the theater near me decided to start showing it on July 2nd. I have no complaints and caught the 11:35 pm showing.
I would say that it helps, but is not necessary, to also be familiar with Beast Wars. This movie doesn't just draw from the original cartoon. If big explosions are what you want, then this will satisfy. The story was not good; it appears they took many liberties developing it. This is not meant to be thought-provoking.
I would give it a 10/10 for computer graphics mastery and 3/10 for the story. The puerile humor did not appeal to me; Michael Bay must still be 12 years old or something.