Personally, I've stuck with the bigger brands, either Shell or Chevron, and had no issues. I did get one batch of Valero when I tried to save a few pennies and regreted it with a marathon regen. That was the first and last time..

Here are cetane values of different brands of fuel. I snagged this list from an old BMW post some time back... Forgot where exactly. I'm not sure if price varies with cetane levels.
If I'm not mistaken, the user manual for our trucks explicitly state cetane of 50 or better is recommended.

Love's 40
Pilot 40
Valero 40
Sheetz 40
Flying J 40
Holiday Stations 40-43
HESS 40-45
Husky 40-45
BP 40-42,47
Exxon/Mobile 43-46
Sunoco Gold 45-50
Shell 46
Sinclair 46
PetroCanada 47-51
ConocoPhillips through the 76 stations (California) 47-53
Chevron 49-51
BP (Amoco branded) 51