A full license for UDK is quite pricey, so isn't really germane to this discussion.
If you need to develop in C++ then your cost structure (in cash or opportunity cost) means that worrying about paying $1500 for a development tool won't even move the needle.
Maya / Max seat $5000+ (and devs tend to need them too)
Unity's biggest payoff is in workflow. If what you care about is the most polygons on the screen then UDK or Cryengine will win. If you care about the price of getting something out the door and it isn't an FPS then Unity clearly wins.
I meant that even if you can afford the full licence and get the C++ source, that doesn't mean that the engine can make any kind of game you want. It's not really a question of constraint by language so much as the way the engine's built.
If you need to develop in C++ then your cost structure (in cash or opportunity cost) means that worrying about paying $1500 for a development tool won't even move the needle.
Maya / Max seat $5000+ (and devs tend to need them too)
Unity's biggest payoff is in workflow. If what you care about is the most polygons on the screen then UDK or Cryengine will win. If you care about the price of getting something out the door and it isn't an FPS then Unity clearly wins.