That’s a very good question. I haven’t rendered anybody with hair in a long time, because it’s just too slow. Essentially look at the promos and exclude those with baked on highlights, unrealistic textures, or insufficiently defined transmaps (look for lose strands and see if the hair fades realistically or not). If you are in the Platinum Club take a look at the hair in the Plat Club (e.g. Jade Hair, Classic Rolled Hair, Trixy Hair all look good to me). I also like a lot Neftis models but the texture, although very good, is of too small a size usually. Reby Sky Elite Hair is also probably a good choice.