I have had two 3-wheeled Zapps (Olive and Steel), and really liked them. They turn on a dime and have that unique look. We don't carry alot of stuff in our stroller, so the storage wasn't a major issue, I have connected a Skip Hop bag low on the back when I needed a little extra space. My son was 3-4 when we had them so I never really worried about the harness, just used it as a 3-point occasionally, but I could see that being an issue. Tipping was not a problem for us, but a heavy bag on the handle could do that, since it is so light weight.
The fold definitely has a learning curve, but once you get it down it is very simple. Getting it in the storage bag however is a totally different story however. We seldom used our bag for this reason. ITA with the other posters who said this wasn't a stroller for an infant. For one that little the Quinny Buzz would be a better fit.