I'm disappointed that I ran into two major obstacles getting started:
1) I couldn't create a new "Mobile" project. The option wasn't even there, despite pointing to my Android SDK. Restarting fixed this.
2) When I created the mobile project, it failed saying "Project Creation Error: Error creating project. Please try again." Not a very helpful error message. Again, restarting fixed the problem.
Sam, I feel your pain. The first troubleshooting point seems to always be, "Have you tried turning it off and on again?"
The lack of polish with Titanium (Titanium Developer being wonky, break-downs when installing new SDKs, undocumented properties and methods, inconsistencies in behavior between iPhone and android) is the deep-seeded issue of my love-hate relationship with this framework. When I tried out the Titanium Profession Edition service for a month, I felt like I was paying Appcelerator for the privilege of doing QA.