I have not used a LiPo but I am thinking of trying it out. One area where LiPo's are superior is that they have a nearly flat voltage curve. The longest mains I ever run are about 30 minutes but even then I notice the brakes going soft if I haven't re-peaked with Nimh packs. This should be unnoticeable with a LiPo since they have very consistent voltage for the duration of a charge.
"I have no idea what you're talking about, so here's a bunny with a pancake on it's head."
In mind and body, we're all heading towards old age. It is slower to go by bike.