Here are some discharge graphs of the packs I'm looking at. It compares the same capacity packs of different C-ratings. The only real difference I see with the bigger packs, is that voltage under load(25c) of the 30c packs is higher at the beginning of discharge, and halfway the 25 and 30c packs perform similar. In the end the 25c packs last just a little longer until the cells reach 3v/cel. The 25c cells do get a bit warmer, but nothing to worry about.

http://www.elektromodellflug.de/akku...power-line.htm