The 405 is the prior model (and they don't make it anymore if I recall correctly) and was widely reported to have issues with it's touch bezel, often making it useless. Now, some people still love their 405 and swear by them. I'm just giving you the info that I've got!
I have a 405 and have bezel issues in the summer when I sweat excessively. Usually when humidity is 85% and above. I started wearing a cloth wristband under it and its fixed.
Another question - I noticed the 410 comes with additional wristbands which is a major plus for me since I have small wrists. Can you sub out the band on the other versions too? The 210 or 405? I can't seem to find these anywhere except in the 410 bundle...