Don't get me wrong. I have success with the DIY tumbler, but if I can do something better, I'm willing to give it a try.
I don't have enough air pressure in my tumblers with the big batch of eggs I just pulled. Appears there is a dead spot where the tube and the bullet fitting meet on inside of the tumbler. The eggs bouncing in the middle seem to push some eggs to the side and they settle sometimes for too long and I lose them. Maybe I'm the only one with such luck.
I am taking one for the team and will let everyone know how it works and if my hatch rate improves. I emailed back and forth with the guy for a few days. He has me convinced, sales line or not, he told me I will get close to 100% hatch rate. Excited to experiment.