I've been using CL for a decade now - I used to trawl gumtree, too, before they did away with personal ads.
It's a bit hit and miss but luckily for me I travel all over the country for work so I have the whole country to work with. This year has been my most successful year to date - I've had 11 sessions with 11 different women in 2016 (mostly in London). I rarely read or respond to the ads on there but I put my own ads up so women contact; I have about 5 ads running at any given time and I just bump them up everyday so I show up on the first page.
You have to invest a lot of time reading emails and responding to the ones that fit your requirements. I'm also on fabswingers but I haven't had a lot of luck there - only met 2 women and a cuckold couple in 2 years. Fabswingers is great if you want to attend swinging parties and clubs and want to go to gangbangs. I'm not interested in any of those hence the low success rate.
If you just want to pump and dump, punting is the best but if, like me, you enjoy the intimacy, the overnights and the hanging out and the knowledge that the woman is fucking you because they fancy you and therefore is going to make an effort, the time investment is worth it.