Gewa chin rests can (putting stress on can) be very worth the price, they are really cheap, and sometimes you may be lucky. But usually you get what you pay for. The quality is inconsistent. If you have one that fit perfectly, the other one may be awful. The metal hardware is also rather bad. It does not operate smoothly at all and the holes for turning sometimes are too small for a regular chin rest tool. Sometimes the holes in the chin rest are not drilled perpendicular which results in the chin rest not being level when mounted. But as I said, once in a while you may get lucky, and in that case a Gewa chinrest is a bargain.
If you want consistency in quality and shape, go for Conrad Götz, but be prepared to open your wallet as well.