I went out yesterday with mine for the first time. I had the Garmin Edge 500 prior to this.
Here are some of the things I like:
-Larger Screen: Allows for more fields while still being 'viewable'
-Quick satellite acquisition...like real fast.
-Garmin connect(ivity) via Bluetooth sync
-Allowed me to send a "Live Tracking" link to email addresses (so my girlfriend can find me if I'm laying in a ditch somewhere, or she's feeling frisky lol). Can also share "live tracking" with twitter and FB. Allows people to see your location as well as your avg. speed, total ascent, etc.
-Once my ride was over, I clicked 'save' and it automatically uploaded my ride to garmin connect.
-I clicked to view my activity on my phone and was able to see my location and stuff just fine. This will be a great way to meet up with your friends riding, or people on a group ride, etc.
-There is a loop and a lanyard...so you can attach your garmin to your bike.
-Comes standard with an "out front" mount. I had a k-edge anyway, but cool that it comes with one now.
-Multiple modes...for example, I can click "Train" and have a certain set of default metrics shown. then I can click "race" and can have an entirely different set of metrics shown...just sorta cool.
-User interface is revamped and a bit more intuitive. Easier to customize things that you want to, etc.
Things I don't like:
-Doesn't sync with Strava
-The 'connect' features aren't quite as robust as how they market it...but I imagine they will continue to develop and roll out additional functionality.
-I can't seem to figure out how to configure the 'auto-pause' (which I'm going to google right after this post)...so my avg. speed looked like crap because I had to stop a few times.
All-in-all... definitely not disappointed!