I think it's going to be for real teams , having very skilled coders that would be able to study and understand it's complicated code and bring on new stuff !

For indie and lonewolves , others engines i htink are lot more suitable with their simple scripts and better documentation/tutorials.

But Garage games also provides other very good products like their Torque 2D or incoming Iphone (only 2D for the moment)
But will their Iphone product will be as easy of use as Iphone of Unity ?