I've used only the Valvoline Premium Blue in any of the diesels owned since 2003.
A Duramax, then 2006 Cummins, and now 2011 Powerstroke Ford.
I still purchase mine at the Cummins dealership in Sioux Falls SD. Last time they were out of stock locally on the 5W-40 so they had it shipped up for me from the Cummins dealership in Omaha Nebraska. This was earlier this year, so I can only assume they still have some sort of working agreement with Valvoline on this oil.
I wish I could recall or even find it again. But some time back one of the diesel enthusiasts web sites performed some tests on the new CJ-4 oils. Rated them on the various properties of each oil.
The Valvoline Premium Blue was number one rated diesel oil in their study.
It has surely worked fine for me running 5,000 mile changes on the Duramax and 2006 Cummins. Now with the Ford and the built in oil change reminder, it appears to be running in the 7,500 mile range on the Powerstroke.