All I know about Edinburgh Fringe is that it's something of an endurance test for upcoming artists and, like many things, it greatly favours those with money rather than talent. I saw a documentary (or news report, can't remember) which detailed how it can cost thousands to attend the Fringe as a performer. Accommodation costs skyrocket, and some venues ask artists to pay for a timeslot to perform in. So it has become a horrible, cynical cash grab, which can cost thousands to merely attend as a performer.
Beautiful city anyway. I was there quite recently, and would definitely consider a permanent move.