I use two 2s1p TrakPower Lipo pack wierd in series for 4s. I was going to try and get run times today but ran out of time.
Seriously I think it is around 20 minutes. Next time I get a chance I'll measure for you. There is a thread here that is stickied for run times. Maybe check it for info.
I am using (2) 8000mah 7.4 Maxamp lipos in series, I havent had chance to run long enough to measure my times yet....also been wondering if the single 5000mah lipo will be enough run time for the e-revo would love a 8000mah 5s pack for it, but I bet that will be huge and very heavy...I like maxamps especialy the 3yr/300 warranty, what warranty do the flightpowers and NeuEnergy's have? I know maxamps is not the most powerful though... more middle of road performance vs Neu or flightpower batteries from what I have read