I'm not doubting anyone's experiences, but for all the talk of stales, I rarely see any with slush. Also, my miners don't spontaneously crash (you should fix that), so the score based system is fair to me. I also don't get my panties in a wad whenever there's a hiccup or some variation messes with my expected reward.
slush has been responsive to every issue, actively fights ddos, and is active in this thread. That's about all I ask for.