PhoneGap and Titanium allow you build native iPhone Apps based on HTML and JavaScript.
Has anyone gained experience with both? What are the differences?
It's probably worth following the current Apple/Adobe spat, in which Mr Jobs has put the future of products that aren't written in language XYZ in the balance. OS 4 SDK states:
Applications may only use Documented APIs in the manner prescribed by Apple and must not use or call any private APIs. Applications must be originally written in Objective-C, C, C++, or JavaScript as executed by the iPhone OS WebKit engine, and only code written in C, C++, and Objective-C may compile and directly link against the Documented APIs (e.g., Applications that link to Documented APIs through an intermediary translation or compatibility layer or tool are prohibited).
I believe Titanium is affected by this.
There is a pretty lengthy discussion about PhoneGap VS Titanium (and Corona) on StackOverflow already that might be useful.
One of the big differences is that PhoneGap is MIT licensed and Titanium is (just recently changed) Apache licensed.