I've been using LiPo batteries for the last 5 years in my Trex 450, 500 & 600 along with my electric planes too... they are something like half the weight with 1/3 more power than NiCads...and NiMetalhydrite ..... I've never had issues wity them providing they're used properly..

Really surprised they haven't taken over the LiIon batts in phones ....