S&Box and Gmod

The development of sbox (gmod 2),and development began on UE4but not Source Engine.
Is it good or will it be able to outperform Gmod?

I think that if he refuses the content css / hl2 then it's bad

Nah it will be way better then gmod, because unreal engine 4 has no limits u do whatever u wish to do

I haven't had any experience with the Unreal Engine as far as I know, but I'll be surprised if it'll top GMOD.