I was having good luck with it until my last 2 batches. My last hatch I ran 3 weeks ago only 8 chicks hatched out of 22 eggs!
I'm wondering, when you clean the unit, have you checked the fan?
Each hatch, I find a whole bunch of chick down up there. I use a Qtip only very slightly damp and carefully wipe it all off away from the fan motor. I've also opened the top and removed the fan on one unit that had gotten rather noisy in the last day of a hatch... cleaned that fan more thoroughly and greased the motor with a rubber safe lubricant. It was quiet after.
I just hatched 38 chicks out of the 2 bators on Friday, so I'm still pretty pleased with it. I do wish cleaning was a bit easier, but it's hard to imagine a design without funky spots for stuff to get stuck.
To make sure the turner operates, don't forget to reset it each time (Menu and Minus button held down until it beeps).