If you are comparing the 70D and the 6D, you must be a bit confused about the 6D, since they target very different uses imho. More pricey does not always mean better suited for you.
The 6D is great for image quality and low light, and being FF, with WiFi and GPS in it is more than tempting, even for those more adventurous that go outdoors hiking. But notice that it's not too well designed for outdoors, action, nature and moving subjects:
- It only offers 1 cross type AF sensor in the center. The rest are vertical or horizontal aligned only. Not good when you need precise focusing or autofocus off the center.
- 4fps: not good for nature or sports.
- No flash means you'll always have to carry your 580EX or whatever you use, in your bag. This can be tricky if you go mountaineering and try to avoid too much load.
Don't get me wrong. I sallivate when I hear 6D (or 5DMkIII!), but the question comes to... is it _that_ what you actually need?