I have a thermpen now. I used to have a cheap wireless meat temp thermometer but I quit using it after serving pink chicken to my family. If you only grill then cheap out. If you cook a lot spend the money on good equipment.
By good I mean a pt-100. A thermapen is very nice but a thermo-couple should do. The copay for 2 people getting food poisoning or the time off from an undercooked chicken for just one day pays for the better equipment. That is how I justified the cost.
Current Smoker: Char-Griller Kamado