No complaints with mine. What's really great about it is you can use it for anything. You can keep track of multiple vivs, roach bins, your oven and your car engine all with the same device. I was even using it for a while to temp the bath water.
I highly recommend reading the operating instructions that come with it. You might be tempted to skip it because the device is rather self explanatory, but don't. there's some funny jokes in it. Here's an online copy of it. http://www.tempgun.com/PE-1_operating_instructions_1-05.htm
Mirage came out of brumation on April 26. He was doing great. On May 2 he started acting funny. We just redid his tank, and he keeps going into one of his hides. He just lays there. He shows no intrest in food. HELP!