Answer: -Kohler Wellworth -I've had good success with the Briggs -We put in two, based on plumbing company's recommendation. They've worked well, completely flushing each use almost without exception. For a new addition, we've just specified another Vacuity. -I installed a Vacuity about a year ago. Works great. Not to be gross, but.. Sometimes, if it's got a lot of poop in it, it will evacuate all of the big stuff, and leave some small remanents. It's only clogged on me once, but it was understandable. I won't elaborate on that at risk of getting more gross. I don't regret it.