My only complaint against them is I tried to buy a battery tray from them so I could swap the battery between my Rad City and my 48v homebrew bike, and they refused to sell it to me. (Edit: To be clear I went back a couple of months later, told a different story, and got one.)

I also had a battery charging issue after 1000 miles and a winter where it got unplugged from the charger for a couple of months, but I count that as my mistake. I got to take apart the old battery pack though, and one interesting thing I found was that although the power output has half a dozen electrodes on it, only the two big + and - ones were connected to anything.