I'm fairly comfortable with Unity, but still have a ways to go. Actually, I've found it to be kind of hard to get used to because everything has to be done the Unity way. The editors make up for it, but I think the way it's scripted is kind of round about and hard to organize. It seems kind of backwards in a lot of ways. I have to spend hours pouring over the script reference to figure out how to do something. The tutorials are full of details, but short on overall organization. A game manager class would have been a good idea. Most tutorials don't even use one, so your stuck figuring it out yourself. The first thing most people do is start adding way too many scripts on the main character, GUI, everything. I'm still not sure I have it the way I want it, yet, and I'm working on about my third try at a game. I would have to say, scripting wise, it's the most awkward engine I've ever used. On the plus side, it's the easiest engine I've ever used to get a model into it from Blender, other than the Blender game engine. The GUI is pretty decent for a built in. The physics are decent and built in. All in all, good, but scripting, blah.