I watched Lagann-hen yesterday, it was chock full of nostalgia and win for me. There were some changes made to the narrative again but most of my favorite scenes from the second part of the show were still there in one form or another. If you thought the final battle in the show was epic the final battle in the movie had the epicness level turned up to around 15, however to gain that boost of epicness on the positive side they sacrificed some of the negative elements of the show by eliminating the events of episode 25.

All in all I would recommend this to any Gurren Lagann fan who wants to experience some of the awesomeness of the show in a compressed win package, however I wouldn't recommend it as a replacement for the series itself as a lot of the interpersonal experiences (other than Simon and Nia's) are diluted for the sake of the more epic battle scenes.