I have just got the GoPro Hero 4 session because they dropped the price! But haven't had a chance to use it for cricket yet! Did some stuff last year with my hero 3. The problem I found with GoPros is their 'range' when mounted on the bowlers end stumps the batsmen is quite far away! Meaning you have to zoom in in editing, which reduces the quality!
Here is an example of it from the bowlers end, I know it isn't that good because I had it mounted at the bottom of the stumps but it gives you an idea.
https://youtu.be/WoFvAedhqn8 The lighting was OK in the nets (indoor school at county ground Taunton) but the GoPros do best with bright natural light.
The GoPros do better capturing what's going on in front of them or coming towards them. Here's a video I took with the GoPro mounted behind the net.
https://youtu.be/2F-mgEfwZ6EHere is one of my better net videos, using the GoPro as a helmet cam and then my DSLR on a tripod way back behind the stumps using a 70-300mm lens.
https://youtu.be/_SXMGk5d9o8 (yes I do leave 2 straight ones in this video! Followed it with 48 not out on the weekend though!)
Hope that gives an idea of how you can use the GoPro and what its strengths are, I'd say it's better mounted on the helmet or inside the net looking at the batsmen for cricket stuff. Having it mounted on the stumps at bowlers end doesn't give you the best view of what's going on. I did do a club video where I had it on the umpires head, that hasn't made it onto YouTube yet mainly because I'm unhappy with the quality of the footage, overcast skies meant not the best light and the umpire cam being a little too far away.
The newer GoPros do have a choice of field of view where you can change the wide view for a medium or narrow one. This would give it a more 'zoomed in' effect. This could be better for cricket but I haven't had a chance to try that out yet, maybe simmy has been able to?