Mel is correct, most of this has been discussed. Here are the short answers, but you will want to dig deeper to find in-depth discussion of each issue.
1) A number of folks have used the regenerative controller. It seems a few different revisions have been fielded, but there is limited technical information available.
2) Someone describes a setup where he uses a switch to selectively disable the regenerative braking, however this has not been well described and the poster did not describe how well he liked it or how it was used.
3) Sealed Lead-Acid, Lithium ion or Lithium iron phosphate are the most common. Some folks run on NiMH or NiCad.
4) Lots of discussion about front vs. rear. Each has its advocates. Front for weight balance and simplicity of installation. Rear for 'stealth', better steering handling and more strength available in the rear dropouts.
5) They back their product 100% if the failure occurs during certain planetary alignments. We haven't been able to determine which planets are the important ones for this to happen, so it seems rather random. The rest of the time you will never hear from the company after delivery regardless of the severity of the problem. Posting to this board never results in a response from the company as it doesn't change the alignment of the planets.
