Yes, it's usable. Performance wise, STATS does intercept up and down messages and compute stats based off of that,so there *is* a (small) performance price you have to pay. However, you *could* write your own STATS protocol if you're only interested in some stats, but not all, e.g. by copying STATS and removing stats you're not interested in, and possibly adding stats.
Maybe STATS itself could be made configurable in order to minimize the overhead implied?