This was about 5 months ago, so it's possible they drastically improved it in that time (although it doesn't sound like it). But I ran into the exact same issues.

Debugging was a pain because of you were writing JavaScript rather than Obj-C and the line or file on some errors were on were entirely unhelpful.

Performance (which you don't notice in the simulator) is poor. I was working with tables on iOS, even after cutting the app down to using 10 rows, people noticed a lot of lag on iPhone 4s (and it was unusable on a 3G or 3). This was with the only scroll events being a scroll position check suggested by the KitchenSink demo they provide.

Entirely possible this was something I missed, but while it says cross-platform, you don't really get cross-platform. The difference in UIs between Android and iOS means you're going to be writing quite a lot more code to actually get an app that works on both Android and iOS.

[edit] syntax