When considering runtime and charge-time, LiPo is not more expensive. One battery will perform like 2 or 3 NiMh packs. This is especially true in racing. With NiMh, you need a pack in the vehicle, one on the charger and one cooling off after use. I race an RC10T4, sometimes in two classes. I use one 6000mah pack and one charger. That's all I need.