Well, the Garmin Edge 305 arrived from tvnav.com and I wasted no time getting it installed. Here are a few of my thoughts.

First off, the main question answered: It really is a nice bike computer! The screen is very readable and being able to choose the number of fields displayed and where each field is displayed is great.

Installation was simple. The cadence sensor attaches to the left chain stay with two zip-ties. A magnet attaches to the left pedal and another to a spoke. It took me less than 10 minutes to get that installed. The only minor glitch was that the zip ties had already been "zipped" at the factory, but fortunately I had spares. The Edge itself mounted nicely on the stem and felt sturdy in that location.  There are no rattles, like are heard with other Garmin bike mounts.

I went for an easy 26 mile ride, which you can see at MotionBased. The Edge proved to be easy to use and read while riding. I tried to do a course with a virtual partner, but I guess I screwed up, because I couldn't make that happen. Will have to experiment more.

I would also like to recommend SportTracks, which is a fantastic logbook for GPS-enabled devices.  It incorporates all of the GPS and Heart Rate data and incorporates the data into useful and fun charts overlaid on street, satellite or topographic maps.

This example was more challenging. The path was wide and winding with an elevation change.  I was also going pretty fast -- in excess of 20mph. The Edge tracked correctly, but the other three each had error.

If you want to look for yourself, here's the Google Earth file that will let you compare all four.
 

Elevation accuracy was another question.  This PDF file shows the elevation plots for each of the four devices.  It's interesting to see that the Edge and Vista tracked almost exactly the same for most of the ride, including being almost 100 feet high at the beginning of the ride.  This is due to the barometric altimeter which takes over an hour to calibrate itself.  On the other hand, the altimeter eliminates elevation changes due to changing satellite geometry, so overall, the readings should be more accurate.  By the end of the ride, all of the devices are pretty close to the same value, with the Edge and Vista continuing to track almost exactly the same.

Installation

Here are some installation pictures:

The cadence sensor with spoke and crank magnets:
 

Close up of the GSC-10 Cadence Sensor:
 

Stem mount for Edge and handlebar mount for Vista:
 

A touring configuration. Since the Edge doesn't have mapping per se, I think there's still an occasional need for the Vista. Note that the Edge screen is a lot brighter. Part of that is because of the flash and the angle, but it really is easier to read than the Vista:
 

The complete dork setup. This is the configuration I used to get the side-by-side tracks above:
 

Here's the view from the saddle:
 

About Courses and the Virtual Partner

A meeting ended early today, so I got to sneak out for a ride over lunch. it gave me a chance to try a course and the virtual partner and all I can say is...

Wow!

In TC, I created a course from last Saturday's ride and off I went. Unfortunately tracks imported from other Garmin devices will not currently work as courses, so I'm stuck with this one. I hope Garmin and MotionBased fix this soon, as I'm anxious to trade courses and use some of my older courses!

Anyway, it's cool and motivating. I found that I spent the entire ride on the course screens either trying to catch up with or stay ahead of the VP. On the hills, you could see the VP pull ahead as he crested before me and it was quite clear on the altitude profile page. The map was fun, because I could see the course and see the VP's position relative to mine, see him stuck at stop lights and make turns, but really the gold old VP page that we all know and love from the FR series was where I spent most of my time. I had that up and displayed my HR Zone so I knew when I could work harder to catch up or stay ahead.

Anyway, I knocked 2 1/2 minutes of my best time and I did that by keeping my average HR only 1 beat per minute over my previous best.

Courses

Here are the four "course" pages. The first fields on the top half of the screen can be customized (up to four fields).

Sorry this is a little blurry. This is the first courses page. The bottom four fields are fixed with "distance to go," "time to go," "course point distance," and "max speed." Course point distance is for a course point that you would have added via TC:

The second page shows the course map. The black triangle is my position. The gray triangle towards the top of the screen is the Virtual Partner:

The third page is an altitude page. The circle to the left is my position and the gray circle is the VP:

The final page will be familiar to any Forerunner owner and it shows the traditional VP page:
 

Here's a closeup view of the Edge 305 and Forerunner 305: