The Result Was Very Bad All Bitcoin & Cryptocoin Exchanger Have Too Many Scamming Reports
You have to admit first that there's no perfect exchange, all of them have problems about deposits, withdrawals, coins listing and etc.
Why not state what are these exchanges that you have used and encountered problem with it? as long as you never used the exchange and you are only depending on the bad reviews of most that will stop you to use but if you have good experience on that exchange, you will stop?
Scam means you get nothing and those reviews probably are only getting their withdrawals delayed but later they get it.