Hi,
over the last 45 years I have witnessed the products of DB' lubricants approval process
In the early years an "Approval" booklet was produced and this covered all lubricants and greases. It was both brand, application, type, viscosity and MB engine model specific
It was a succesful process then - and still is now! Some of their engines were very "hard" on the lubricants of the day - especially their diesels - use a non approved lubricant and you suffered the consequences
Having worked for Caltex-Chevron in Denmark and Daimler Benz I can assure you that the Approval process was Warranty "binding" and taught many persons many things about Tribology and etc.
I have visited Stuttgart, Worth and Sindelfingen many times and understand the Global marketing needs from the MB Engineers. As well, absorbing the disasters of failed dynasties like British Motor Corp. - Leyland!
I used MB approved lubricants ( with specific knowledge of their engines ) in "problem" engines from other manufacturers during the 1960's and later with great success. Those manufacturers at the time were not only the more well known names like Volvo, Ford, Opel etc.but Moskvich, ZAZ and etc.too
Whether they are as strict today I do not know but I can tell you that within the last 14 days here in Australia, ExxonMobil witheld marketing a batch of Delvac 1 in order to amend the labeling to satisfy the requirements of DB ( now of course DaimlerChrysler )
I have always put a great importance on the Approval of Porsche ( owner ),MB ( ex owner ), VW Group ( owner ) and the MIL specs.
ACEA is also there to satisfy the needs of these and other Euro manufacturers - as a counter to the USA's standards which led the World in a general sense for decades.
Better or Worse? Well, "different" and to meet their specific needs!
The Euro philosophy on engine design has always been different due to the various cultures, tax requirements, use factors and the over riding needs in enviromental management ( remember acid rain/Black Forest ? ). And manufacturing standards too!
I still purchase my lubricants and fuels ( about $A200 000 annually ) using the measures noted above - and the needs of my equipment. If I see the MB Approval and Porsche too, I feel more comfortable
Regards