I have an edge 305 and found the best tool for it is SportTracks. http://www.zonefivesoftware.com/SportTracks/

I wrote a review of it here-http://ww2.rochesterflyers.com/reviews/i-wanted-to-write-a-full-review-of-sporttracks-20/

It's donation ware so you try it, and if it's worth it to you, you pay what you feel it's worth. There are many plug-ins to tailor it to what you need. The training load plug-in give a WKO+ type of training analysis.