Wow, Paul, I have three Geratherm Mercury-Free Thermometers, and I haven't had a lick of trouble with any of them. I also experimented with their basal thermometer version, and while the numbers were easier to read, when I took it with me in the heat of last summer, it broke. Otherwise, it was very nice. Just better left at home.
But just now, I read some reviews on Amazon, and there were some unhappy people. All I can say is, that was not my experience. If you know that your digital is reliable, you might stick with it. My mother won't give hers up :)