Which is more accurate? It's the ages old question that can't be answerred. There is no "Atomic Clock". There are lots of variables and methods out there. I think most would agree that staying with the same lab throughout the life of the vehicle is your best bet. You can evaluate trends better that way. I will sample all of my vehicles at least once with DA though, because I think the lab that they use has more sensitive techniques and methods for analyzing fuel%, flashpoint, and coolant. They are also a much better value when you consider what all they analyze and interpret. Terry Dyson is without peer in his interpretation. If you just want a basic UOA that shows resonably accurate wear metal and additive content, a $20 UOA from BSL should be a favorite choice.