GET THE DIGITAL!!! Didn't mean to yell but I fiddled around with those wafers for years and always had to adjust, up, down, they can stick, etc... My digital unit heats up to the exact temp in 5-10 minutes and STAYS there without ever being touched. The only adjustment you may need to make is when you first set it up. Mine ran a degree and a half too high. I set it down lower and it is perfect. I have the full picture window as well and the temp usually varies maybe .2-.6 of a degree, ever. I don't mean to go on and on but I cannot tell you how nice it is to have excellent hatch rates - some 100% - with this unit. I will never go back to a wafer.
Richard