I run a Thunderpower 3cell Li-po at 1350mah on a mamba performance kit (5400k/v) I was getting about 20 minutes on a regular 5 cell 6v 1100mah pack. With my li-po seems like I can drive all day long. With my regular Ni-Mh pack I could only pull wheelies on carpet with step pins on. After my first run with my Li-po I can pull 200ft wheelies in my parking lot and my tires were bald after 40 miutes of wheelies and 40+ mph runs. I was confused about Li-po's as well before I bought one. I saw a video on Google videos of a Li-po blowing up on a charger which really had me concerned. But after doing some research and talking with people at my LHS that use them I bought one and I'm loving it. Once you get over the initial payment for it which mine cost me $50 for the pack then $50 for the Li-Po charger and another $60 for a AC converter due to the type of charger I bought. It's not that bad. Just make sure you stay on top of the packs you cant leave them on the charger like the old Ni-mh packs Mine takes usually about 40 minutes to an hour to charge and with my charger I can charge the pack from my truck battery as well when I'm out at the park running my cars with my friends. Trust me If you are cautious and can read some direction on how to use the lipo's your car truck or buggy will thank you for the massive power these things hold. I easliy get double to triple run times over the Ni-mh's and the power that is available is amazing. Talk with your LHS about it before you buy one they can steer you in the right direction and answer questions you have about them, also hit your local track and see them in action, talk with drivers using them.

Li-Po's = A+++++

Ni-mh = last place.