Unfortunately, my experience going with a kit has not been good. I went through Sun Coast Electric Bikes and the battery failed after only my third ride. At first, my contact was quick to help. However, once we narrowed down the problem I haven't had any contact. I naively expect to have a replacement on my doorstep pretty much everyday.
In retrospect, I wish that I would have worked with someone locally. That way, if there is a problem, you can work directly with them. I hope to have a positive update to this story soon.