del.icio.us or diigo-Which bookmark is better?

After opening a new account in both del.icio.us and diigo I have found them both to be interesting ways of boolmarking websites that are of interest and great use. I have watched the YouTube videos for both sights and there are certainly benefits to each one. Even though I have to play with them a little more I think the diigo site is more interesting. I like the idea that you can put sticky notes and highlight text in a sight as you are reading. We all know how handy that can be. I don't have the time to use this capability right now but do plan to use it in the future as I compile a list of websites to use in my future classroom.