My arguments for staying with lower capacity (500-700 mAh) NiCd batteries are:
1) They give me more than enough capacity for the amount of flying I want to do in any given day.
2) They are inexpensive and highly reliable
3) They last a really long time. I have some packs that are 7 years old and still cycle and self-discharge like new.
4) It is a simple matter to charge them overnight with a C/10 wall wart for the next day's flying.