Why run these?
If you bash or run modified, or perhaps run on a slippery offroad track, these are perfect.
They charge in 15 min for a 2s1p pack and when the batteries run dead, instead of slowing down gradually, they'll drop within a half lap, all of a sudden the car will almost come to a stop.
I ran a 6 min main with an mf2/5700 mamba with a 2s1p pack ( 6.6v 2300 mah) with no problems on a medium sized track.
They do have new packs out that are similar in size/shape to the hard case lipo packs, without all of the babysitting that a lipo needs.