I have a Trek insight 8 wireless that is great dead accurate and has never had any issues in 4000 miles except I had to change a battery. I also have a Garmin Four Runner 305 that I use with it being a runner too. The Gramin it dead accurate in my last century the garmin had 100.15 miles and the Trek 100 even. I like using both but I had the garmin for running before I ever had a bike computer so finally I simply bought the bike computer. I use the wheel roll out method to get the Trek at the best level of accuracy.