I have used them for a pretty long time with no problems. In fact they have wowed me a few times.
Some people have had accounts closed due to sharpness. Playing steam and/or playing both sides of a bet seems to be a recipe for problems. I think they have been generally pretty professional about closing accounts although, as I recall, BAUS may have had a freeplay removed.
Betjoint has had some recent setbacks with Neteller processing. They will work with players in alternate methods upon the players request, though, and do book-to-book with some of the big boys.
The claim the "fastest payouts", but who knows these days. I actually used them when they fist opened without problems, like 1-2 years ago..
They are offering a 25% freplay but so is Bookmaker.
Stay away from BetJoint. They have an MO of sponsoring contests at different forums, then find a way to not pay out prizes after the season ends, claiming not enough participation. This has happened on at least 2 forums that I know of for football seasons.
I opened an account and made a $1k deposit, and they stiffed me on the prize money.