I have been working with Appcelerator’s Titanium Developer over the past couple of days and I must say I am very impressed. Some people liken it to PhoneGap in that you write code in javascript, css, and html but that is where the comparison stops in my opinion. They both do generate native apps that can be installed onto the iPhone and Android. (Titanium does not yet support BB). Titanium provides a lot of native looking widgets that you would otherwise have to create yourself in PhoneGap. I did run into an issue the other day though with trying to use the API.info() for logging. It seemed to be an issue in the builder.py which a friend of mine and I fixed and blogged about here.
Give it a shot and let me know what you think.