I did switch bators last year. I had an LG and received a Humidaire, so I just got the Humidaire up to temp/humidity and made the switch. No problems, hatched just fine. I think it was about day 13 or 14 when I switched.
Good. I have eggs that I will have to switch around next week. I ordered some from here and have some already started so I need to do some shuffling around.