I had a "0.67 String Shootout" on my MX80s. I posted it somewhere.....maybe on this thread. Anyway, to summarise, I tried ZM67, BG80, BG80P, and VS850. All on a pair of MX80s at the same tension. ZM67 - New kid on the block, good combo of feel and power, slight edge towards repulsion. Red colour looks awesome. BG80 - The classic all-rounder. Doesn't do anything badly. People complain about durability but I've never had any problems. BG80P - Not sure where the power is, but there is none at this tension. I think this string would add durability for high tensions users and probably be great at 30+lbs, but I couldn't be bothered finding out. VS850 - Seductive feel in the front court, very tactile string. Great all-rounder with slight bias towards tactical game. Loses tension easily so needs a good stringer.