Good exchange are loaded with features as follows:
1. Centralise, 2. Good volume, 3. Scam free, 4 easy to deposits and withdrawn, with all this features mentioned above I can say that an exchange is good
Scam free? There no exchange that do guarantee full safety yet all things are hackable.
Centralized? Typical thing on most exchangers existed as of this moment.
High Volume? With this indicator alone you will able to know on which exchange been trusted or been used
by crypto community which signifies a good exchange on end.