Any 10 year old Merc is going to be trouble, they’re not that reliable and the build quality was a patchy. 10 year Golf would be a better bet
I've got a CLK 270 cdi diesel. It drives beautiful, handles beautiful, has been no trouble and if driven sensible does about 35mpg in town and over 50mpg on a run. They are different but Merc still make a nice car. PM me if you want to know more.
Got an E220CDI Estate 2008 had the previous model and also a AMG C32 The 220cdi and 5 speed box is bullet proof: paint/ bodies up to 2004/5 had issues, petrol engines had cam chain problems. But Merc's are great cars all makes have issues? Ask Bike folks not many would have a Triumph but we will!!!
I've got a 04 reg C180K and never spent any money on it since i bought it (about 8 yrs ago). Now got 34,000 on the clock, original battery, brake pads etc. Just had to buy one set of tyres about 2,000 miles ago but have had no problems at all. Rides a bit hard compared to some Mercs but it is the sport evolution model. On my bike most of the time, hence the low milage