I haven't grown the "ruffles" variety of purple basil. The Dark Opal serves ornamental purposes each year.
I have given up on some basil varieties that aren't fusarium wilt resistant. Lettuce-leaf is just a disaster! Nufar is very trustworthy and a good basil.
Lemon basil, especially on salmon, is really good but, for some reason, my wife doesn't seem to appreciate it. (I will just have to resign myself
Of the Thai basils I have grown, Siam Queen has been the best and quite a bit better quality than the others. I am still waiting to have the quality of what I get at the Thai restaurant, however. I suspect that it is grown in a greenhouse and benefits from the protection.