I haven't ran a 592 or a 661c so I cant have an opinion on that, THATS WHY I WAS ASKING YOU. If I had ran them, I wouldn't be so concerned with your opinion because I would then have one of my own. For the saws that I have ran and compared, ms660, 390xp, 372xp, 372xpw, 576xp, ms461, ms460...