I used to have an old Zero SR, and it was a bit of a mixed bag. Here's my observation:
Pros: It was super easy to ride, just twist the throttle and go. If you could charge at work, it was like free gas, and even charging at home was cheap, though.
Cons: The range was all over the place and not great, charging took forever, it didn't really have any personality, it was tricky to handle at slow speeds, it wasn't very fast, it felt kinda dead to ride, and you never knew where you could charge it.