It has always been my preference to end up in the P12.
The geography and travel make a lot more sense than the B12. Plus I know all the teams in the P12 pretty well. In addition, overall, the locations of the P12 schools are much more desirable destinations than where the B12 schools are. But because of the incessant, repetitive messaging that the P12 would never take BYU because of philosophical differences, bias, not a research institution, etc., etc., I started warming up to the B12 and became, over time, a big proponent of one day joining the B12, partly, at least, because I've always felt that the door to the P12 was forever closed.
However, if at some point BYU was presented with legitimate offers from both the P12 and the B12 at the same time, I'd say yes to the P12 in a heartbeat and wouldn't think twice about telling the B12 no.