Actually quite compelling, if you overlook the vast liberties taken with history and physics, and the suite of carelessly-contrived plot devices, and the conclusion that leans towards the trite. McConaughey gives an impassioned and credible performance, and the photography is very well done.
Also worth noting is the quality of the production design, and particularly the interior of the U-571... helped, I'm sure, by the fact that U-571's production designer just happened to also have been Das Boot's art director.