Haven't bought anything but sold stuff with no problem.
As long as you exercise the same common sense you would buying anything (does it seem dodgy/too good a price etc) then you are generally ok.
Yeah it's great, never managed to buy anything but just missed out on a ping G25 5 wood that some guy had for sale for £35 he'd only hit it for a week
Bought a few things from there. Got a virtually brand new Titleist bag for £50. As others have said just use same caution you would when buying off ebay.