GoPro session 4 or GoPro Hero3+, What should I get?

I'm interested in buying a GoPro mainly for the Video features rather than the still pictures. The session 4 should be superior with its 1440p or 1080p60, but every comment i've read says that hero3+ video is better. Why is that?

Secondly, how fragile is the session4? Since it lacks a protective housing like the previous versions, will it break easily?

I'm mostly interested in skiing and surfing, so the minimal size isn't priority.

Since the session4 started with a similar price tag as the hero4, every comparision i've read revolves around the two of them. Now that the price is pretty much cut by half, i think its more relevant to compare it with the hero3+.

Thanks in regards,
Olle

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