I personally prefer Graf.
Last I 'heard' was that Graf is same as Benz dealer pumps.
I tried the other brands before in the C280, did not last. However that might not be due to the brand.
My 300D and now the C280 has Graf.
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1979 300D 220 K miles
1995 C280 109 K miles
1992 Cadillac Eldorado Touring Coupe 57K miles SOLD
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1979 240D 140Kmiles (bought for parents)

*SOLD.
SAN FRANCISCO/(*San Diego)
1989 300SE 148 K miles *SOLD