Just to point out to all the haters on this thread, Mono for Unreal Engine would also include the Mono API’s (which are pretty much a subset of the .net apis). I shouldn’t have to point out that many people find .net easier than C++ simply because whilst the standard library is a great improvement, and whilst UE4 provides some useful utility classes, .net still trumps them massively on the utility class front.
But, my personal advice would be to learn C++. Once you learn all the verbose UE4 annotations (and they are very verbose), it’s almost as easy as C#.