The reason I ask what you will be using it for is to determine which set of features you need. If you're going to be using it for simpler activities, don't go all out for a Black edition with a 60fps, 1080p cam (all HERO3's are 1080p, anyways). The reason the Black Edition is so expensive is because of the crazy quality it has, and if you're using it for a more simple basis I wouldn't worry about the difference. The Silver or even White is perfectly fine for you. The main difference between these two is the white's camera has a 5 megapixels with 3fps burst while the silver is 11 megapixels with a 10 fps burst -- is that worth $100 to you?
What GoPros are compatible with the app?
To get right to the point of my writing: I can't give you a definite answer. What I can definitely tell you right now is that we are to focus on the GoPro HERO4 and HERO3+'s (and I will touch base on a few HERO2 and original 3's as well), as it is the best technology and provides options for numerous consumers. With the recent announcement of the HERO4's especially, we'll tackle the main features of those to help you decide if that hefty price is worth it.
GoPro is leading the charge toward consumer-created virtual reality (VR) environments, and their first VR-ready cameras make it happen with what they’ve dubbed “spherical capture,” which is pretty accurate, given the 360° field of view they record. VR is still a nascent technology, but it’s definitely the future. If you’re an early adopter, you’ll want to pick up a GoPro with spherical capture.