- Well lubed drag-and-drop asset pipeline.
- Pseudo component based makes it easy to start.
- The API is not bad and the documentation is ok also.
- Creative user community creating many well crafted plugins and assets.
- Supports almost everything. Playing McDROID on your VW beetle's dashboard? Yes. You. Can.
- Mono develop is slow on the latest SSD, and sucks in many other un-funny ways.
- If you are an artist, the UI API will make you a very miserable person and will accelerate your aging.
- Iteration cycles are a bit slow since you cannot type your code as you play (.NET scripts need to be compiled)
- Can't bake navmesh at runtime (means if you want to do level editor in game, you need to use a third party nav API)
Conclusion: Get it, it's not bad.