You're kidding right? The MB manual although baulky and clunky is a work horse compared to the auto. Also a major overhaul on the manual doesn't come even close in price to that of an auto overhaul. Having said that the auto will last beyond those of other manufacturers, MB autos ar bullet proof compared to those.
It boils down to your preference and the availability of qualified technicians in your area to deal with your auto. I have found that people who are used to slicky smooth manuals hate the MB one with a passion