What brand is the best for mercedes use?

It doesn't make any difference. In order for a product to carry the "Dexron III" label it must pass a very comprehensive series of tests, and only a very narrow range of base stock and additive package will pass all the tests.

If you had access to each brand's certification test results you might be able to sort through it and find a brand that exceeds the test requirments more than any other, but whether it is "better" would take real world testing.

Anyone who claims their brand is best is just regurgitating marketing hype. The same applies to motor oil and most other automotive fluids.

Duke

Dear Duke: Wanted to let you know that I have silver , split window coupe, 1963 with 340 HP, 410 rear end, and 4 speed manual trans. No frills, no power steering or pwer brakes, no a/c 86000 miles, original owner! stay in touch. Abe G

My SWC is in restoration, and will again be the original Riverside red/red, 340 HP, M20 close ratio, 3.08 Positraction, J-65 Metallic brakes, and AM radio. It was built on March 19, a Tuesday, and I have the dealer copy of the production order and lots of other orignal paperwork from the St. Louis factory delivery.

The 76 MPH first gear does not make it a very good around town driver, but back in the sixties there were few cars that would exceed an honest 150 MPH. My SWC did a couple of times, but with the crude aerodynamics is was a pretty wild ride.

Duke