I wouldn't suggest them, check this scam accusation:
https://bitcointalk.org/index.php?topic=5110287.0It's also worth mentioning that If you're planning to run an exchange, it's much better to code it yourself or hire developers and security experts to do because even If the website you're buying from is legit, you could never tell if its poorly coded or contain backdoors as you don't have the necessary knowledge.