We also need to get past this BYU fan-fed delusional idea that Utah's accomlishments don't merit an invite to the Pac 10 (at least when compared with BYU's). Granted, I'll be the first to admit that if BYU did not have the religious tag and Sunday play attatched to it, they would have been invited before Utah. They have a much bigger fan base nation wide. However, the only reason they have that nation wide fan base is the religious affiliation, so you obviously cannot have one without the other.
In regards to who's "earned" it more, I think the clear choice is Utah. If we look at MWC history (since 1999), Utah has won 6 out of 11 in the rivalry and the two schools have the exact same amount of MWC Titles. However, Utah has busted the BCS twice, won both games and has a much, much better bowl record than BYU during that time.
If you want to go back as far the WAC years, obviously BYU gets the edge, but the Pac 10 isn't concerned about the WAC years and why should they? That was a bad conference with bad teams that BYU easily dominated. Utah hadn't arrived yet as a program, leaving BYU largely uncontested.
Yes, if you'd like to go back to 1984 I'm sure you could do that, but then again you come across looking like Uncle Rico. Live in the now. In the current climate, Utah has been the better program with the signature wins. Don't like it? Go win a BCS game or 2.