Tough choice because Glenn is probably one of the best fighting characters in the game, if not the best. However, Razzly is also very cool, fun and useful character. My favorite party consists of Serge, Kid and Razzly (replace Kid with Karsh when she's not in your party). In my first game of FF, I chose to be a good friend for Kid and try to save her. ^^ On my 2nd game, on New Game Plus, I think I'll choose not to save her and get Glenn. That's what I'd suggest you to do: choose either choice on your first game, and the other choice on New Game Plus.