My rims are double wall, so they do have that going for them. In any case, they should last long enough to give me a break from spending money on the bike after converting it.
Something people often cite as a reason for going with discs is the added weight of an ebike. Fortunately for me, I'm only about 130lbs and my bike is 34lbs, so even with the motor and batteries, I'll only be at about 200-220lbs total.
I rode my bike to and from work yesterday after lunch. The speed to be able to keep up with traffic would be nice (most drivers gave a good amount of space when passing, though). The biggest drawbacks are the heat and wind. It was only 80F but I felt like dying because I was riding in uniform and had a backpack on. I can do without the backpack (just couldn't find something smaller to put on the rear rack), but I'm pretty much stuck with the uniform. Wind was either calm or at my back on the way to work, but was about 10MPH against me going home, which hurt my time. I decided the knobby tires have to go, they feel pretty unstable at 15+MPH. I'm thinking of getting
Continental Double Fighter 2's to replace them. Reviews are pretty good for them and they help with rolling resistance a ton. Only con is they don't last a super long time, but not bad for the price and performance.
I'm currently considering a Crystalyte motor kit from ebikes.ca. They're more than the ebay kits and the MP3, but are held in higher regard from what I've seen. And they come with a Cycle Analyst (pretty much the ebike version of a SGII) which is $120 on its own. Pretty much set on the 48v 15Ah Ping battery.