PhoneGap projects require the installed SDKs for building the applications and the coding is done through Xcode. PhoneGap then renders files during the building process inside a native WebView Objective-C or Java. Access is provided to native features including the contacts list and the Accelerometer and even the camera functions and list notifications through its API.
The actual interface uses HTML and CSS which gives an altogether different look to the interface elements including buttons and the performance will differ from that of the native elements.
Compared to PhoneGap, Titanium can convert the code into native application code. The app code is being interpreted and written in JS. It runs during runtime through bridge layer too.
In Titanium, building and packaging does not happen within the IDE unlike PhoneGap but through Titanium Developer, the software. The tool can set up the new projects and even test them or package them. Any IDE of the developer’s choice can be used for writing the codes.