I bought a complete Surly Big Dummy with the E+ kit in November 2010 and though I would post a little about it.
I have well over 600 miles on it so far and no issues with the E+ end of it at all. About all I had to do so far is a little fine tuning on the shifters, same as any other new bike.
I had a flat rear tire in the first week or so and that was no fun, luckily I was close to my LBS.
Everything about the kit seems great. I don't have any experience with other Ebikes so I have nothing to compare it to.
The list (very small) of things I would change all have to do with the controller and display. There is no way to lock it onto MPH for the readouts and if you're not careful it's easy to end up reading KPH on the display, then of course it's not so easy to change it back. This is mostly an issue with gloves on and the dark doesn't help. I guess a light on my helmet would solve some of this.
The Big Dummy is a great bike, I'll be getting a lot of use out of it.