Speed and Cadence Bike Sensor Opinions I'm looking to start tracking my speed and cadence for my iOS app, Cycle Meter.  The app works great for distance, time, but is not accurate at all for measuring my speed. 

So I'm thinking of buying a Garmin or a Wahoo speed/cadance sensor and wanted to get the community's opinion on the two.  I'm not worried about price.  More about quality, functionality. 

The two in question are:

http://www.wahoofitness.com/Products/Wahoo-Fitness-Premium-Speed-and-Cadence-Bike-Sensor.asp

https://buy.garmin.com/shop/shop.do?pID=1266

Update:  been using the Wahoo one for a few weeks now and have to say that I'm very happy with it.  I've been in a lot of rain as well with no issues.
Fady listening to music while riding is probably the most dangerous thing you can do so do not explore that idea please.. With that said I use the edge 500 and it has loads of functionality and will most likely support all your needs. You will usually need to purchase a speed/ cadence sensor with it. Battery life is great so long as you have it set to turn off with inactivity. I do still carry my phone in my jersey pocket when out alone just in case somethin happens.