Recently purchased this. Short version is that it works, but it gets clogged when using it in the boiler. I have not tried it in the mash tun.
Long version is that for beers with highly-converted malts and low/no adjuncts and (probably leaf hops) it performs well. For adjuncts, less converted malts, and pellet hops, it has to constantly be scraped off with a spoon or paddle.
Previously, I just ran from a 1/2" NPT nipple to a 90 degree elbow in the pot and just used a stainless scrubber/sponge stuck on the nipple to strain. This is cheaper, but can still clog.
I remain unsure of the proper answer. I really don't want to spend the time and energy and (lotsa) money to setup some kind of whirlpool. However, when the kettle gets stuck and the wort is coming out of the counter-flow slowly life sucks.
Anybody have a cheap and easy setup that works?