Most of the exchange the fee are almost the same. It because some new exchange doing promotion that why got some discount. By then attracting a lot of users, after that facing traffic issues. Most of the exchange also face the same issues that heavy traffic on their website and became slow loading on websites. Lastly the more important things is the exchange is safe, this only my concern. If the exchange can guarantee is safe and I willing to pay the fee.
Above only my personal opinion and concerns.