Big Al, I like to use a calibrateable bimetal thermometer. Every few brews I calibrate it at mash temps using a certified lab thermometer. Something to consider.
Tell ya what: if(when?) I break one of my lab(-style) thermometers, I'll replace it with a certified lab thermometer. If(when?) The other one breaks, I'll try a good bimetal thermometer. But it just wouldn't be pragmatic to replace them before that since I'm happy with what I've got. I do understand that although my process works for me, my recipe may or may not be repeatable on someone else's system. Then again, is any recipe truly transferable from one system to another?