I think he is a really good college coach. Have no idea how he would fare in the NFL. I don't think he could be any worse than Garrett though. Plus he would probably pair well with Moore at OC to help him be better.
Three things I like:
I like that he worked his way up and earned promotions. That's always a huge plus for me. I don't like coaches who are simply anointed into positions.
I like that he's had great success at both of his head coaching jobs. That tells me he's the system and his success isn't dictated by bringing in a top 15 recruiting class.
I like that he seems to get the most out of his team. He doesn't waste talent. The only year that I think you can make an argument that his team was a bit of a disappointment was his 2018 Washington team. That team was still pretty good and went to the Rose Bowl, but coming into the season they had a very experienced QB (Browning) and were playing in a weakened PAC 12....so most assumed Washington would make the playoffs. Other than that, I think he's lived up to most people's expectations each and every year.