My lhs is overpriced as well, but there were weekend when I would break something on my T4 and I could drive up and buy the overpriced part so that my weekend was not ruined (instead of waiting till midweek for parts via internet).
Whereas I bought my mp777 roller before checking to see that none of the 3 hobby stores in town carry kyosho parts, so if it breaks on Saturday (practice) I am out of the game on Sunday, unless it is one of the parts I have spares of. Although I always seem to break something I don't have any extras.

Edit:
Maxamps aren't very well liked on this board. I have some and they seem to run great, but I don't have much experience with them yet. Additionally you can't be quoted a runtime without picking the mah as runtime is dependant on mah.