Our shop car is a 2013 ML350 that has been great. Comparing it to other German cars its a lot cheaper, not as much to fix as a VW and parts/labor are way cheaper than a BMW. Coworker bought the other shop car, a 2014 335XI, and its had more problems and all of them have been stupid how much the dealer wants to fix them. The MB dealer is half the hourly rate of the BMW and I can find parts on rockauto if I need. Can't do that with a beemer. All that said, our ML350 just developed an issue where the AC decides when it wants to work along with some other weird gremlins.
On the SL top, we had a similar issue on the bosses SL550 and it didn't cost no 1500. His son in law rallyed it and set off the sensors in the "rollbar". We just had to reset them, basically push them back down and the top worked.