Thermapen will always be considered pretty much the best. However, I didn't want to spend that much. I went with the RT600C. Same brand, but only $19 on amazon. Never had any accuracy/precision issues (I've calibrated it) and its spent about 72 hours totally submerged in my swamp cool after my cat knocked it in. No problems at all.
Watch me leap through this hoop!
On Tap: Rocketsauce IPA, Party Ride Wheat
Fermenting: Meet Your Maker Stout, Big Ring DIPA