Honest question from an outsider: it looks like Epic and Crytek have finally gotten around to moving in to the "low-end" of the game engine market. What's still unique about unity?
2. Being first to indie market: community and asset store.
It can save time in the beginning and you will prototype early.
Easy to use and easy to access.
The revolution in competition for indie game development platforms is here. I don't know why Crytek is doing, but Unreal Engine is very usable and amazing technology.
http://blog.interfacevision.com/design/design-visual-progarm...
Also Unreal Engine will be fixed soon ;) - Xamarin is working on C# scripting for it.
2. Effortless porting. See 1.
2. Stock assets delivered with the engine - that's pretty valuable if you're indie.