I watch this type of programming in spurts. My main interests in watching these types of shows is to learn something of value or some interesting trivia. Really do not watch any of the competitive type shows unless it is a cooking related show; not so much for the competition, contestants or host, but to see if there is some interesting bit that I can apply to my cooking. Of the "cooking" related shows that I most commonly watch would be Diners, Drive-ins and Dives.
I absolutely cannot stand the series that profit on drama or stupidity. Do not want to watch a bunch of women (or men) scream at each other or other "youngsters" have drama in their lives. There is enough stupidity in the world already without watching it purposefully on TV. I do not suffer fools. I used to watch American Chopper in the beginning when they would actually show a lot of the builds but then it became too dramatic for my taste.
My favorites are the ones that have some historical or educational significance. The British have produced several of these that focus on archeology or some other historical events. PBS has a few that I enjoy catching from time-to-time like Antiques Roadshow, History Detectives, Finding Your Roots. I will also catch American Pickers. These types of shows provide an interesting backstory on people, places and things. Not sure if Aerial America fits in but it is a nice production as well. Another one to watch is How It's Made.