1996 and up Mercedes 300E DIESEL, can anyone tell me the facts about the problems on these models.?

computor problems, yes/ no, trans problems ,electrical problems or even motor problems, what seems to be the most problematic issue of these cars if any, and if i bought a well cared for car, with let's say 150,000 miles and it had no known issues, i take it home put mobil one oil in it change the filters, include trans filters and fluid then take car of it like its a baby could it go 350.000 miles without blowing the head gasket or putting a crank rod out the side of the block? many people have said they are NOT as good as the old mercedes diesels OK', but is this to say they are not worth buying, could a car that cost $35.000 or more be a pile of junk after 150.000 miles, i'm not sure i understand the facts as to why people are not saying good things about the 300E-diesel, I love the body style and the inside comforts but is that all the car stands for, is their no quality left in the drive train who of you work on this type of mercedes can you give me a idea about the car's thanks.