It started right up after sitting 6 months? Buy it.
Does it drive well? Buy it.
Do you want to get a major education on working on MBZS? Buy it.
My advice to anyone looking at Benzes is, if you are willing to work on it yourself, they are great cars. If you are not, you better have very deep pockets. Living near salvage yards that have junk ones for parts is a major plus.
but you say " Any repairs are gonna be done by a mechanic," and a "regular guy" to boot.
That sounds dangerously expensive.