We just bought a shotkam in the club. Depending on the background and lighting you can see the shotstring.
In the settings, you can choose between 1/1 1/4 1/8 1/16 speed. And then if you go to VLC player, you can go frame by frame. On the tablet/phone you can set the playback speed down to 25%. Then it will take forever to see a shot, but every little detail will be revealed. (if you record in 1/16 and playback speed is normal, it will take almost 2 minutes to watch a shot!
When you adjust the crosshairs before going shooting, be meticulous!
I have experienced that it doesn't record some of the shots, why I can't tell you (have an idea that I haven't closed the gun hard enough to activate the recording, but that can be adjusted in the settings).
It's a good tool IMO but with limitations. It can't tell if you lift your head, or swing the comb of your face on right handers (presuming you are a right handed shooter).
I'd suggest team up with the rest of the club and by one. Then the cost isn't that ridiculous.
Lars