I have the Planet Bike one with the thermometer. Sorry, Sandra, I forgot to get back with you on this. Anyway, I had to bend the prongs by the battery because it wasn't making good contact, but that was the only issue. It doesn't have cadence, which I didn't want anyway, but I did like the thermometer idea. Cyclocomputers aren't hard to install. There are directions with them and you just have to follow them. Putting in your wheel size is probably the worst part because they (computers) are all different on how to do this, but it's all in the directions. Since you don't have to run wires, just line it up on the wheel and voila! Took me about 15 minutes. I have the Planet Bike Aero and so far so good. I think it was around $30 at Performance Bike.
Claudia
2009 Trek 7.6fx
2013 Jamis Satellite
2014 Terry Burlington