My mare is a grade, I bought her because none of the registered horses I tried out were not good enough, terrible conformation, not trained, over budget, or not trained in the right direction (EX western pleasure, hunters). My little grade mare has done all western speed events, jumps, has worked cows a few times, and did english pleasure classes. Reason they got rid of her, because she is a one person horse, doesn't like having different riders all the time so she didn't work for a lesson horse. She is suppose to have been a registered quarter horse at one point but have no proof of that.
I have 2 grades. One is a purebred Curly that never got registered. The other is his half brother. I know their pedigree's/bloodlines but it doesn't matter to me if they have papers. They'll never be top show horses.
I have a APHA mare though and her foal will absolutely be registered once it hits the ground. I prefer a horse with papers because the value is higher, but I don't need them.
2 of my 3 are grade. I supposed the Appy/Arab could have been registered if I wanted, but why? He is a good, level-headed horse who gives you his all. My BLM mustang is also a good horse. The only questionable one is my registered, sweepstakes nominated Arabian mare. I'm the only one who rides her. If you looked up "Arabian mare" in a dictionary of stereotypes, you would find her picture...
My horse is grade. To me, I don't "judge" a horse by their breeding any more than I would judge a person by it. They all have their own personalities regardless of their bloodlines, and I didn't buy him to win any awards, just to enjoy his company and have some fun together.