Are you guys looking for the best rates in the market when deciding to buy/sell Bitcoin or you're bond with the certain exchanges where you have an account?
Of not, there are a lot of exchanges out there, so I don't understand why you're stuck win just one. And to add to that, just a precautionary measure, don't put everything in an exchange though, better have your money in a wallet that you control over with.
It's also good to experiment and experience other exchanges though, regardless of the exchange rate, just saying.