Another bonus is that AdultFriendFinder is like the dating site version of New York City (AKA it never sleeps). You'll find people who work the regular 9-5, people who work the night shift, and people in other time zones, so it's nearly impossible to log on and not have people to talk to. AdultFriendFinder is like the booty call that's always awake when you text them.
The features of the European Dating app should also matter. You want something that is simple but functional. They should be perfectly suitable even for technologically-challenged individuals. Their compatibility feature should have the capacity to match you with the ideal dating partner and they should not make a random suggestion. They should have different communication feature that allows you to communicate with the other members with ease.