I have a Wilderness Energy brushed system, 36V at 12aH. I have had it for 4 years now. I don't ride it every day, I ride a pedal bike to work but occasionally pull out the ebike. Its on a Giant Sedona with a front suspension (very nice). I still have the original tires, they are very fat tires on a 26" wheel, not sure of the width. I seem to get about 10 miles per charge, maybe 14 before the red battery light comes on solid, however that is running full power all the time, not hypermiling. I suppose if you pedal enough you can go an infinite distance on one charge
I get a new battery pack every year, for about $125 delivered. It has been very reliable, in fact no problems other than I had to replace connectors when I first got it.
I'd like to upgrade to a LiFePo 48V 20aH battery, maybe next year if I have the money. I hear the brushed kits can do 48V no problem. That should increase range by quite a bit, maybe even to the point where you can ride until your butt can't take any more.
My experience with the Wilderness kit is that it is very reliable and long lasting, even though it is one of the cheaper kits out there. I'd probably go with a Crystalyte next time but I can't complain too much about the brushed WE kit.