Read some DIY threads on DF or DP it is not that simple of a DIY when you make one mistake read a few of the stories and finding that check ball that got loose etc. These shops are taking one heck of a risk for just the $250.00 for the install, $250.00 for fluid if they exchange all the fluid. One mistake or complaint and they have "bought" that transmission.
Just to get out of town I may just take trip to California and plan a few places to visit while I'm there...
Great point! Risk vs reward. Name your price and make it worth it because your name and reputation is on the line.