Jeff,
Some might disagree with me. But unless you are distance racing don't bother with the electronics.
As Dave said, GPS based devices (Ie. speedpuck) are not F18 class legal. There was a last minute amendment allowing them in Corpus but this won't happen again unless the class changes the rule.
Yes there are times where the compass can be good to have but 90% of the time it's just going to be a distraction. Save your pennies for coaching or new sails.
The speedpuck can be a good training device, but again not legal for racing.
I have a micro and haven't used it in 3 years. Most of the top F18 sailors feel the same way. You even see less and less of them on dinghies like Lasers, infact most of the top Laser sailors in a class where it used to be used by all the top sailors, do not use them anymore.
-Todd