As someone who just owns horses because I love riding them out on the trails, I could care less whether or not the horse has papers. Really!
But if the horse has papers, that's like icing on the cake. It is nice, but not a necessity.
I have almost found the opposite to be true among some people I have met. They are almost anti-papers, because they think it is somehow snooty or something!!?
The one thing I find nice with papers, is to know their true age and where they were born. But otherwise, I don't show, so I don't mind either way.
Hmm. Out of the horses we have had, 3 have been registered (two Arabs and a Foxtrotter) and two have not (a Mustang and a Paint). The horse I paid the most for ironically is the Mustang! But he is wonderfully trained. My Arabs and Foxtrotter were relatively cheap, so I don't know if the papers really add to their value unless they have outstanding show potential to go along with it.
So I would always put the horse before the papers, and choose a wonderful individual without papers over a mediocre one with papers. Of course I am not a show person or a breeder. If I were, then papers would be more important to me. To me, training and temperment are the most important, and good conformation is a plus. Papers are way down the list and basically a non-factor.
I will also go as far as to say that purchase price doesn't have much to do with the value of the horse either. You can have a cheap, wonderful horse, or an expensive horse that isn't worth owning!
It would be easier as a horse buyer if a price could be put on a good horse, then you would know what you had to pay to get one, but alas, we can pay good money for bad, or little money for good!