I've installed it and really like it. The tube is more than long enough as I have my ATO tank on the right and the top off is on the other side of the cabinet.
What I realized is if I fill my ATO tank to the top, the tube is lower than the max level of my ATO and so it keeps dripping even after the ATO stops (like a siphon effect). So I have to fill my ATO tank to the same level as the end of the top off tube, or raise the top off tube higher...
The pump does make some pretty loud buzzing that I can hear from inside the cabinet. Not too bad as it only lasts a few seconds.
Another thing I found is that while testing a power off situation, when power is restored the unit sometimes automatically thinks the water level is too low and starts topping off a bit of water only to stop a few seconds later and causes the "water level too high" alarm to go off.