The difference in a young coach like Pastner and Capel at the time of their hires is the experince factor. Pastner always knew he wanted to be a coach and worked at his trade long before he even finished playing. He coached the Houston Hoops AAU team as a 16 and 17 year-old. He had no illusions about a NBA career and thus helped the AZ coaches with scouting and recruiting before his playing days were done. If I remember correctly he gave up his final year of eligibility so he could start spending more time with the coaching staff. He then recruited at the high-major level for 7 years at Memphis and Arizona before being handed the HC job when Cal left for Kentucky. Even though he only made the NIT in his first season at Memphis, he was named CUSA Coach of the Year by some media outlets for keeping a roster competitive that was ravaged by Cal in the same way that Sampson's recruits bailed on Capel (X Henry, Cousins, and Bledsoe were all headed to Memphis). His team this year started 4 freshmen and was the 3rd youngest overall in the country. If he does stay at Memhpis his team will be a force over the coming seasons.
While I won't say he is best coach to fill our opening, I don't think anyone really knows who the best really is. I do know that if he is the one hired, his background by far exceeds Capel at the same juncture.