personally, I'd like to keep my Mercedes original using the oe coolant. Whenever someone brings in a pre purchase inspection, I check the coolant type. 10 out of 10 times, if it has the oe coolant, that usually means it is dealer serviced or done by an indy shop that knows MB's. Which in turn, is usually a better maintained car. If it comes in with dexcool, I can usually expect coat hangers in place of exhaust doughnuts, black tape over the check engine light, non-metric hose clamps, and a bubba's quick lube oil sticker running non synthetic oil in a 2000 MB.
Dave