I love these strings, have been using them since they were called MSP-3100, they are strong, resilient, with a nice clear tone that has a metallic sound to them, to begin with, that I love. It does dull after 1 or 2 weeks of medium use (20-30 mins a day).
Great for performing with, and all-around really good.
As far as I recall, I've only ever had one string break on me early.