A short take:

Rating: Null/10 (28 April 2000)

U-571 is definitely not the best way to spend your movie money. The least of the problems are many inaccuracies to actual WWII history, naval tactics, and science, which makes you wonder who, if anyone, did the research for this movie. Even if no one did the research this movie still should not be so uneducated.
Even if you ignore that fact and see this as a sci-fi thriller it is still not a good one. First of all, the characters are extremely shallow and they have absolutely no personality what so ever. There are many great opportunities in the movie to move the audience emotionally but the director didn't take advantage of them. The fact makes the movie very emotionally flat. The actings are not bad but the actors' efforts are wasted by the poor directing and script.
Ok, so you say you are not here to watch an art movie and you don't care. Well, the actions aren't remarkable neither. The lightings are poorly done which make the actions very confusing. The action themselves are pretty brainless with repeated let-rush-blindly-into-the-danger-and-pray-we-somehow-survive tactics in every situation. The trailer is certainly misleading which want you to believe there's an "entire German fleet chasing you down" but the scale of the battle is actually very small. Don't expect an epic battle, there are only two boats chasing each other.
I am very disappointed at this movie and would urge you not to give your hard earned money to encourage the production of poorly researched, poorly executed mass-market-junk like U-571