I got the Wahoo TICKR several days back. It is pretty much a one for one replacement for the Garmin - at least based on early usage. I did not have any trouble getting two different (Garmin) computers to connect to it. And the flashing LED could be handy if there was a connection issue and you weren't sure which end of the system was the problem.
I am assuming that when the time comes, the coin sized screw slot will allow me to actually replace a dead battery using tools that I own which includes 3 (all different brands) 'precision screwdriver sets'.
dave