I bought 2 of them right after they were introduced and I tell you what - the wife and I hated them! On our first ride, despite the fact that I really torqued the mounting screw, both of our computers departed the mount when that screw backed out. I think hitting the ground might of caused a problem with the circuit board inside because afterwards, neither computer would go more than a couple hours of riding without indicating the batteries were weak - argh. Well at the beginning of December while riding with a friend from Austin, I noticed he also had the CD300 and I enquired to him about battery life. He had owned his for about 4-months and never had a problem. So after nearly 6-months of frustration and countless battery swaps, I uninstalled and boxed them, and shipped them back to Cateye. About a week later we got an Express Mail package from Cateye and there were our replacements including some niffty improvements like thread lock on the moutning screw and a spring on the battery cover to keep the batteries from comming out of the receptacle when you hit a bump which caused the display unit to lose sync with the speed/cadence sensor! Since installing them we have had absolutely no problems and my faith is restored to the point that I am now patiently awaiting them to start shipping the TR100 which has Speed/Cadence/Heart Rate (all downloadable to PC/MAC) in one unit although my understanding is that it will use wired speed/cadence and wirelss heartrate! **Interestingly enough, Cateye did not have a TR100 on display at Interbike last year!