GoPro Hero+ or Session?

I figured this sub would be most knowledgeable. I have $200 to spend and I want a GoPro, I know most people would recommend just save for the Silver or Black but I don't want to drop that kind of money on something like this. So what is the pros and cons of the two devices? I'm looking mostly at low light, video quality, is the Protune feature that big of a deal? I own Movie Studio Platinum 13 if that makes up for anything. Hopefully this is the right sub to ask th