I don't have personal experience of Guntree (yet!) but a friend of mine who does massage uses it in London and gets a ton of calls every day. It's best to pay to be featured and as someone else said be very careful not to sound as if you're offering sexual services because they will remove the ad. Writing something like 'this is not a sexual service' seems to be the trick. Reverse psychology maybe!
I'm definitely going to try it for Edinburgh