Replying to Sony HDR-as15 or GoPro hero 3?

So I'm in the market for action cams and I've boiled it down to these two. The only thing holding me back on the HDR is where to mount it. I know they have a setup where you can attach it to your goggle strap, that just seems like it would produce a floppy quality. Anyone have some input, I've never owned one before. The HDR is cheaper but Go Pro has been doing this for years so I feel like they have nailed everything.