It is MB engines in general though the 617 is among the best. I commute 430 miles a week in my 300SD, and it runs perfectly every time....and I've been getting 25-27mpg depending on where I set the cruise. A coworker of mine is on his third car in 4 weeks! (buys junkers and ditches them when they die....it is costing him way more than I spend on my MB)

If I were to pick another commuter MB it'd be either a 300SD with a 2.88 diff......or a 300D 2.5/300E/400E W124.

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-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)