How do you choose a service to exchange? What factors do you need to pay attention to? For example: I need to get cash in my city, how do I know which service to choose and which to avoid? 
If you don't care much about your privacy you can consider doing a search on registered centralised exchanges in your country. Some reputable exchanges might be restricted in your country. In my country Binance has been banned from operating. You can easily seek redress if you have any problem in an exchange that has the license to operate in your country. The years of operation might be another factor to consider when choosing an exchange. I don't trust some of these new exchanges. Some of them might have fraudulent tendencies.
Popular or reputable exchanges might be better to use than unpopular or unknown ones. These well known exchanges care much about their reputation.