Carter Hall if I had to choose only one. I happen to like OTCs; it's just that they aren't as satisfying in many respects as the top shelf stuff. They seem incredibly mild to me, which suggests a reason why they might be mentioned only with a snicker on forums such as this. Pipe smoking has changed in the last half century. When it's done, it's done with less frequency, due to laws and the attitude of the herd. When a smoker does light up, he wants to make it pay and to get slammed with richness in the form of nicotine or flavor or both. Contrast that with days of yore, when many pipe smokers chain smoked. If I were limited to only one or two bowls a day, there's no way an OTC would satisfy, once you've tasted the good stuff. Anyhow, just a hypothesis.
On the other hand, I believe that somewhere on this forum John Patton mentions that, in effect, the "inferior" quality of OTCs is overstated. I agree. It helps if one is a burley fiend, such as myself, and not one of those hoity-toity virginia lovers, who smoke with pinky finger extended, walk with a mince, and rest their pipes on doilys.