The Workouts feature is supposed to come in early 2010 as part of a firmware update.
My 305 has been trouble free since I bought it used in March 2007. Only accidentally turned itself off once while mountain biking... I fell into a bush, a branch pushed the Stop button.
I read this nice review of the Edge 500 this morning:
http://dcrainmaker.blogspot.com/2009...th-review.html
Like most I would gladly get rid of the 'training partner' and 'pseudo map' features for an extended battery life and a smaller package. I never used the 'pseudo map', and only used 'training partner' once and didn't really care for it. Now does this thing really hold 18 hours? I would love getting some feedback from a real ride experience.
There's still one issue that is keeping me from upgrading: it doesn't work with Ascent yet. The 500 uses a different file format (.fit) and detailed description of the file format is only been released to developers. I guess it should be implemented in most software within a couple of months.