Floating pulley, specialist cam locking tools and a load of other stuff I don't understand.
Basically, a specialist will charge you no more than a general mechanic, but at least you know it will be done properly. ie they will change cambelt and kit, aux belt and kit.
If you take it to Jonny Spanners and his sockets of steel, whats to say he only changes the belt? Then 3 weeks later the tensioner snaps and you're in a whole world of s**t.