digital

I have three of these things, and I am struggling mightily with getting it to work right. I have it turned on, I set the time. No problem. Now, setting the timer, and understanding what is supposed to happen. The instruction sheet that comes with this thing is just not very good. So... I...

What do you all think of digital thermometers vs. the glass one that go in the tank? Is there any specific brand that is more recommended than another? Thanks! -Rich