Well, after trying yarn braids this year, I can say that I would not recommend them to anyone, ever.
They were cumbersome and itchy on-playa, but I kept telling myself my hair would be protected and in the longrun it would be worth it. Two years ago I left my long hair down all week and ended up with nappy dready grossness that took 6 hours to sort out. I thought it couldn't get any worse than that. I was wrong.
I am now about 10 hours into the process of removing the braids. It took me 8 hours to get the yarn out, working carefully but still falling victim to a ton of snapping hair as the yarn had felted itself around small clusters of hair, making them impossible to remove without tearing. When I finished, I had a frazzled head of hair with a ton of broken ends and the most disgusting dreadlock clumps where the base of every single braid was. That's 30 hopelessly tangled birds nests within an inch of my scalp.
I showered, gently shampooed, and soaked my hair in half a bottle of conditioner for 20 minutes hoping to lube everything up and streamline the process of combing, but I don't think it helped much. I am maybe 5% done combing and I have lost an incredible amount of hair, mostly from breakage right at the scalp. I am hoping this won't end with a headshave as I have been working to grow my locks out for a long time now, but at this rate I may have to bite the bullet and start over.
Next year, if I still have hair, I will be going back to my standard of pigtail braids. I hope this helps someone out there.