Having spent a lot of time doing this, I can say that no one place is perfect. FetLife is the best, but it's riddled with flakes who don't show. I can tell you what demographics we have the best luck with.
First, subs are the best. They are usually better educated and more prone to follow through on shoots. Bulls are second worst, only to doms. They both talk a huge game and then flake often. Age is also a factor, people in their 20s flake a high percentage of the time. Guys in their 40s show more regularly. Also, don't think that a "pro" will perform better. We've had amateurs show up and be rock stars, and one "pro" drank all the booze in the mini bar, took Viagra, and couldn't maintain an erection because he was so nervous.
It's a crapshoot. Also, don't plan on long term engagements. Most guys are good for two, maybe three, shoots and then they're gone.
Anywho, good luck! It's fun when you can get it all to work, but be prepared. We find that planning two or three shoots in a day is best, so when someone flakes you don't lose the whole day.