Action 5

Pros

• The 5 is even better. If you think you’re going to be in trails with lots of trees or low light At All. Get the 5
• I looked over this when making the same choice (the 5 Pro had only been out for a few months), and chose the 5 for it's great battery life, ability to save a few shooting settings as presets, and the internal storage. ... No complaints,...
• I think ultimately I’d be happier with just the 5 because the compromise of not being good with low light isn’t there. Longer battery life means less stressing over it. Having the option of 2 mics is nice.
• Action 5 with a mic mini inside my helmet. It would s a great setup. I’ve had great results.
• Otherwise look towards the action 5

Cons

• Action 5 is below the ace pro 2 in my opinion but not by too much and the battery life makes up for it.
• If you like the out of the box look of the action 5, its cheaper and it will probably be just fine for you. Personally, the colors seem fake and processed to me, and there seems to be a lot of noise in shots.
• I will say though, in sun the Action 5 produces a weird trumpet shaped lens flare while the Leica lens flare looks normal.
• Action 4 produces nicer colors than both the Action 5 and 6