Digital Compass - Not a fan so here is my take:
Advantages -
1. The SUUNTO Cobra 3 allows for a tilt of the compass up to 45 degrees. Non-digital compass can lock up if you tilt them.
2. You can hit bookmark and it will record your bearing
3. You can set a bearing and the symbols will tell you your are on course >|< 180 decrees from set course is a box with a verticle line in it. 90 degrees off course (either way) will show a box with a horizontal line.
If you are off course it will point the way to turn to get back on course.
4. It is illuminated in dim light
5. I can adjust the amount of time the compass is on.
6. More compact and streamlined console
Disadvantages
1. I set 6 bookmarks trying to get the $%^@ compass on! This will get better as I get use to it as I have only had it for 10 or so dives.
2. I have to stop and wait for the compass as it takes a continous press for 2 seconds to start the compass.
3. I have to restart the compass the next time I want to take a heading.
4. I miss the ability to look at the bezel ring and just spin it to the desired course, or to look from one heading to the opposite side of the bezel ring to determine the recipical course or a 45 degree turn without having to do math.
In short, I bought the dive computer for the dive computer, not the compass. If I was deciding between two dive computers and one had the electronic compass and the other did not, the compass would not influence me to buy one way or the other. IF both computers offered all the other features I wanted, and price being equal (manual compass on one digital on the other) I woud probably opt for the manual old fashioned compass. I may add an old fashioned one yet to the console of the one I have. I am going to give it another 10 or 15 dives and see where I am.