While in Japan I saw two movies in theaters, Magical Girl Lyrical Nanoha MOVIE 1st and Gekijouban Fate/stay night UNLIMITED BLADE WORKS. So I figured I'd give you guys the ups and downs on each one as a heads up. I'll try not to spoil anything as well.

Nanoha
The movie isn't exactly a recap of the first series, but more of a re-telling. Some elements are different, but most are the same. One example is the way Nanoha met Yuuna and how she first activated Raising Heart. As far as the story goes, it was easy to follow and you can fully understand it without seeing the series. The animation was excellent and the action was continuous. I really enjoyed seeing this movie, and I recommend it to everyone.

Fsn UBW
This movie was a bit more complicated. The entire movie was rushed and extremely difficult to follow. My Japanese friend that was with me didn't understand what was going on and he said he would've liked much more to be explained. Myself (having played the game) could follow it, but I was very disappointed by key elements being left out - Spoilers - Rin using her Command Spells to tell Archer to not harm Shiro while they're working together and Illya's past with Berserker to show their bond (thus allowing him to break Gilgamesh's chains, also omitted) before her death are just two examples. However, the animation, music, and action were all top quality. Constant action, and amazing looking action at that, always kept me watching the screen. This movie I recommend to fans, but if you haven't played the games Unlimited Blade Works route, be ready to be confused.

okay, avoid fate/stay night

I guess I wouldn't say avoid it, it's still very enjoyable, but I guess you don't need to go out of your way to see it if you haven't played the game.