I've got two in a 220, a XF150 and a XF250 on a gen-2 controller. I couldn't get the "OGC" or "LTC" to work the way they were supposed to (though I haven't tried "upgrading the firmware", which I've heard rumors of some folks doing), so have both pumps in forward/reverse, but with slightly differing timings, so that there are periods where the water flows left-to-right, right-to-left, relatively calm with both pumps in reverse at up to 100%, and times when the flows battle for dominance across the top of the tank, creating vortices that sometimes dance into the flow from my return and send bubbles through the tank like a crashing wave on the sea. (That happens maybe once every hour or two.) Forward speed, I have limited to 50%, and even at that they've scoured the sand nearly to the glass at both front corners, and at the front center. Mine are mounted about 6" down on the side panels - deep enough not to have to worry about them during a water change.
Cleaning is simple enough - a bucket of hot tapwater and vinegar in about a 3/1 ratio, and let it run for an hour or two. Rinse with RO/DI, and drop 'em back in the tank. Any powerhead - or anything that's in the water and under the lights - is going to build up fouling from marine organisms, calcium deposits or whatever.
~Bruce