I've read up on the Wahoo a while back. I can't remember why I discounted it, but the one you show doesn't state that it is compatible with Android devices. A quick search didn't show any that were (maybe that was the reason). Frankly, I'd like to think that BT is a standard and any BT compatible device should work with any BT Phone. With these devices clearly stating that they are for the iPhone and with the research I did, I wanted one that stated it would work with Android. From what I remember from a few months ago a lot of people have problems getting the HRM to sync or to stay connected. IIRC, some people had problems after a few months, which would be very upsetting to me. I'm much more comfortable buying something off the shelf at Radio Shack and being able to return it easily if there is any problems. Also, while I
like the idea of a replaceable battery in the Wahoo, I
love the idea of the rechargeable battery in the Sports Tracker HRM. I'm always plugging in my headset and phone to recharge, now I'll just make a little more room for the HRM (I finally used the last USB ports on the bottom of my Monitor). I do realize that it is possible in the months since I did research, things got better / fixed. But, I really like this app and I have no problem getting their HRM to match. I've read where people have used it with other apps. Perhaps I'll test it out with Endomondo for giggles. I liked Endomondo, but it crashed WAY too frequently for me. The longer the workout, the more likely I'd lose all of the data from it.
FWIW: I just did a 2 mile run with the HRM. I didn't charge it before running with it, and I found that I couldn't sync with it during my cool down (I walk my dog for another .2-.25mile). Apparently, the battery died. So, I have it charging in its USB cradle at the moment.
If you want to see the workout follow this link:
http://www.sports-tracker.com/#/workout/Deadken/a9apb9h5eqfttah3
You'll see that you can zoom in on the workout and while you move the cursor along the time / distance / HR chart (I usually uncheck the Altitude as it isn't very accurate), you'll see where I was on the map at that time. Pretty cool and perhaps helpful if I want to see when and where I need to focus on improvement.