I love Zyex strings! I used Helicores, which are also great and by D'addario, for years but switched to Zyex quite a while ago. They have a darker, fuller, and richer sound than Helicores and respond very easily, though they don't have the easy bounciness of Helicores. You're paying style will have some little adjustments if you've played on Helicores, but it's not much of one and you can easily readjust back to Helicores if you go back. I haven't had the problem of getting bad strings the other reviewer had, and I also buy them ahead of time(within a reasonable amount though). I hope that post doesn't give Zyex a bad rep, because they don't deserve it, from my experience. I play both fiddle and classical viola. I've used much more expensive strings quite a lot before on violin, but I love these for my fiddling. My only wish is that they made a five-string Zyex set (but I can easily circumvent that by getting 13-15' viola Zyex C).