Finally and most importantly, a professional support team is what most of the exchanges lacks right now. Technical issues can arise at any time, that's understandable but taking multiple days to respond and fix when people need their money urgently is not something I would like to see in an exchange.
Most important for sure. I've said this every time someone asked about exchange features, and when it comes to 3rd-party services, customer support always stands out and is perhaps the one thing that keeps me coming back, whether it's a casino, exchange, whatever. Open source software even I only use something where there's good community support.
People talk about security a lot and of course that's probably most critical but if you're a typical user like me, there's really not much we can do to find out how secure a platform really is, is there? Just don't store funds there and you de-risk every transaction.
Fees? Costs? Delays? Hassle? I'm willing to put up with a lot of that if I know I can count on prompt and useful support from an actual support service staff. Exchanges want to take on as many users as they can but often severely underestimate firstly the technical knowledge of mainstream users and secondly, their own capacity to process and solve support requests.
An exchange is ultimately in the service industry - keep customers satisfied and engaged, and the rest are just details.
