While I understand that movie-goers enjoy fast-paced action and effects--and the effects here were quite good--they detracted from the story in this case. Some of the more important segments of the story, such as Bela's path of discovery, and most importantly, her understanding and development of her own abilities, were glossed over or skipped altogether in favor of a massive (and yes, fast-paced and exciting) battle scene at the end. Guess it wouldn't have been as exciting to watch Bela enclose all of her friends and family within her shield and simply hold off the Volturi, eh?
In the end, the movie was enjoyable, though, and I must say that they made Kristen Stewart look as beautiful as I've ever seen her.