I've got 5 different wireless thermometers and I have not had any luck with the wireless monitor on any of them. One of them is a Maverick which is supposed to be the best of the best and I don't use it at all because its a POS.
I've now gotten to the point that I have a pretty good idea of how much time it takes to cook something depending the meat and its weight so I just use one of these when I think it might be done http://www.amazon.com/gp/aw/d/B001U5...sr=1-7&pi=SL75
I know a lot of folks that swear by the thermapen but they cost $80+ the thermometer above gives you a solid temp in 10 seconds or less.