So my default string is 66UM, and I recently tried 66F. I previous tried some Zymax string (can't find the name, it was purple/pink and white, and braided). I very much prefer the thinner gauge strings, so I figured why not, and have 5 sets of Li Ning No.1 string on the way. Is anyone using this string, and how does it compare? So far the only comparisons I've seen are, it's like 66UM with a rougher texture and better durability.