3D engines

[Pramitz]

I prefer unreal, everything is pretty by default, and you don't even need to know how to code thanks to blueprint (although you can still use c++ if you want). Also the liscence is cheaper than unity.

Unity is good too though, it really comes down to personal preference

[Pramitz]

1. Personally, I just google individual things that I need to know, and never really read through tutorials.
2. I think that would primarily depend on the efficiency of your own code. The engine should preform fine, theoretically
3. The interface is OK, in about a month of hard work you will probably know your way around it no problem
4. Unreal engine 4, basically. At least those are the only two I would consider working with as an amateur developer

Disclaimer: I am by no means an expert and have yet to release a game, but I have casually worked with unity since late 2013, and UE4 since September.