RE: NiMh v's LiPO
This thread has gone full retard.
NiMH is an old, inferior chemistry. There are situations where they might be preferable to lipo, but they are few and far between. For almost everybody, almost all of the time, lipo is the better option. It provides more power, higher capacity, lower weight, and more voltage options. Both the packs and the chargers are as cheap as (or cheaper than) NiMH if you know where to shop.
But just like uncle Ben said, "with great power comes great responsibility". In exchange for much higher performance, lipos do require a bit more attention - don't over or under charge them, balance them on a regular basis, and don't feed them after midnight. If you can handle those few simple rules, your car will run faster for longer. If you can't, they'll explode and/or transform into gremlins. It's that simple.