I don't grow them exclusively but I have gotten daylilies from nurseries that turned out to be the wrong cultivar and I have purchased clumps that have no names in order to increase my garden. I have 2 areas now, one for the named ones which is kind of a display garden with labeled daylilies and another which contains those unnamed beauties that I love also. You can't go wrong either way. I hope to do some hybridizing this next season and the only advantage I can see between the two is that the registered ones you might have more luck hybridizing because you probably will know if they are fertile or not.