Ive never heard of the Rothco brand, but gear is like airsoft, you get what you pay for. Its even moreso because of what you dont see, such as stitching. It doesn't matter if the material is woven with titanium if the stitching is made out of straw.
Propper is an amazing company with VERY high-quality stuff. Follow the washing instructions and it wont fade much either.
Is it worth the extra money? Yes if you plan on using it. If you just want to walk around and look Tacticool, than go with the cheaper stuff, but if you want to game with it, get Propper.