+1 anthonyrosenthal, It doesn't make a difference to me personally. Although, on one cheap basket pipe I bought, the coating actually started to peel off! It didn't affect the flavor, but it was a little annoying.
While I only have 30 years of puffing I agree with Roth. I don't think a pipes individual character comes out if there is a bowl coating.In my 40+ years of puffing, I've never had a burnout and I believe that if a pipe smoker maintains his or her pipe properly, avoid using torch lighters and/or smoking outside when it's windy, the bowl coating is not only irrelevant, I look as the coating and being an interference between me and the pipe's briar.