You may want to carefully compare the electronics in the kits. I won't recommend one kit over another, or one vendor over another, but the kit from eBikes.ca has a lot of custom electronics with some very nice features. I was very impressed by the knowledge they posted on the website and in terms of product knowledge, I'd rate them very high.
I read Justin's account of his ride across Canada testing the electronics and I drooled over their Cycle Analyst and some of the mods he made to the controller for regen - which may (or may not) be a benefit....