Most stations carry the same cetane rating in my area. There are a couple BPs that carry 'premium' diesel with a slightly higher cetane.

My experience with previous diesel trucks and with a previous career as a truck driver was that the brand was less important than the station. I'd rather buy diesel at a place that had a generic name but that had a lot of diesel sales than at a name brand place that sold hardly any diesel. The more diesel they sell, the fresher it will be, and the less likely it will be to be contaminated. I try to find stations that sell a lot to local truckers...if you want to get repeat business from guys that are buying 90 gallons/day, you have to have good, fresh, clean fuel. I'd much rather buy from a place that sells a lot to truckers, than buy from a suburban station that sells 10 gallons here and there to Mommie Commuter in her diesel Jetta.