I don't love 'em or hate 'em. They're just different. (I seem to be concluding that about a lot of things, lately...)
For me, there's no monumental tongue-saving quality with the draft hole pointed to the roof of the mouth. Nor does it prevent smoke from getting to the tongue. It clenches, for me, like any other pipe, and in some instances, is more comfortable with my tongue in a natural position. Perhaps it's my overbite, or the fact I "side-clench" (pipe bit is on the inside top and bottom of my molars, pipe obliqued to the right or left corner of my mouth) rather than a "front clench" (where I notice guys run the pipe stem/bit in-line with their bottom and top molars, and the pipe faces more forward with their gaze).
I dunno. Comfort issues, I seem to notice, are the biggest complaint with P-lips, so if you have a clench or way of smoking that accommodates those kinds of Petes favorably, you're lucky to have more selections available to you.
8)