Utah was a really REALLY bad football team when many of those guys pre-Sark and Doman played them. And Utah has been a really good football team some of the years since.
Look at completion percentage, TD to INT ration, total yards, PER, whatever you want to include in the discussion. But I wouldn't use beating Utah as the lone measuring stick. From when Lavell Edwards arrived in Provo in 1972 until 1990, Utah only had 6 seasons above .500. Not what I'd use to show any kind of QB prowess.