|Bold claim Unreal... But can you back it up?|
Programming - First impressions would say that for a beginning programmer, unity3D is much easier to learn. Being able to code in the smaller chunks (behaviors) and the availability (asset store, this blog, forums, others...) of free scripts to (steal) use fairly - that the idea of compiling and writing full classes for pawns and actors is a little more challenging. Point for Unity.
Tool Based Assets - However the reverse is true for aspiring level designers. The inbuilt-tools available in unreal for building levels and generating lightmaps are slightly superior to that of unity. Sure Unity has a passable terrain tool and scene lightmapping, but I have all kinds og trouble trying to get that to work right. Point for Unreal.
Outside Assets - Generating assets in outside programs, while not my forte' seems to be easier in Unity. The asset browser in Unreal is convoluted at first glace, but perhaps this is just because I'm so used to Unity. Importing assets from 3dsmax, photoshop and others is 'automatic' for Unity, and a little more of a process for Unreal. But because I haven't had enough time to fully investigate, I can't award a point in this class just yet.
Build Platforms - If you don't buy the extra pro versions of unity, you only get web player and pc/mac. Compare that to the currently available platforms for Unreal of Windows and iOS. iOS is huge in the current casual gaming market and adds a lot to the value of UDK. But if you have the change to buy a full Unity Suite (something like $2500) you'll unlock Android, iOS (forget about Xbox and Ps3 unless you are really serious). Points? Depends on who you are.
Rushed Conclusion after first impressions: For the first time game developer, go with Unity - the web-player is a easy way to get your game to the masses. For the serious developer looking to make money (without investment), my vote would be for UDK at this point. If you have the money, get Unity3D pro.