I chose the 405 over the 305 because of it's smaller size and versatility. I've had it for three years, and use it extensively for running and biking. Overall, I am happy with it and would recommend it over the 305 for the following reasons:
Pro's:
-Looks and wears like a watch, instead of a wrist-based computer.
-Paired with a heartrate monitor and foot pod, I can track all sorts of cool data, seemlessly upload to the internet via ANT stick, and analyze route, elevation, performance, and history.
-Display can easily be customized to show you data on your run that is useful for your unique needs.
-Yes, the touch bezel can be cumbersome at times, but once you get the hang of it, it is really easy to use.
Con's:
-I'd say it has been accurate 97% of the time, with errors similar to jae2460 happening one or two times.
-Short battery life - needs to be recharged every 48 hrs.
-Cost $300-$400 was high, but my ROI is satisfactory with its high usage and utility.