I've used the Edge 305 for the past three days and have been happy with it. I paid $150 for a returned unit at an REI Attic Sale (normally $400), so I can't make any complaints! I hadn't planned to buy one, but couldn't pass up the $250 off list price.
It seems to be working fine--I just had to replace the Cadence/Speed sensor battery. I had a little trouble trying to get the sensor to read both the wheel and the pedal, but I think it is working properly now.
I'll try to get a more thorough review when I have more time to test all the features.