I've been using my Edge 800 for about 5 years. It's never given me a serious problem. It's still in good condition and the battery still has a great life. Mine is mounted on the stem where it's very easy and convenient to see.

Recently I got a Garmin GPS watch which has a lot of cycling features, similar battery life, counts strokes and laps when I swim, has good running features, and a lot more. If I had it all to do over again I'd strongly consider just going with a watch.