I've been a member of AFF for 2 years now and am based in the UK. In my experience only about 1 in 5 members you will interact with will actually be serious about meeting.
I've met one lady locally and another from a different part of the country, If you are UK based and looking to have several different hook ups you probably have to be willing to travel. Although if you live in London you may find more people locally than if you live in the North East. I'm extremely large in the trouser department and that has put some potential meets up as it was too intimidating for them so perhaps my success rate is limited in that sense.
If you are decent looking, not overweight, can converse normally and don't have a micro sized cock you can potentially do pretty well on AFF. If you verify your profile and also get a testimonial early off the bat, then this will increase your chances.
There are some genuine people looking to meet.
You can find people who are looking for adult casual encounters.
Men really need to pay for a membership in order to make enough contact with women to close hook ups. Women can rely on a non paid membership and still get meets.
The site is probably 60% time-wasters.
BigBen does recommend Adult Friendfinder to friends/family