Just buy C3. Stop thinking, start developing!
...but seriously it really depends on what you need.
For mobile game development, C3 is nearly perfect for most types of 2D games. Give it 6 months, and it'll be spot on.
If you know what you're doing, game development with C2/C3 is super fast, and (important for me) 'code' is easily reusable for your other games.