My take for ProShot: It worths it. The current build is not very stable on my phone, but it's still a steal with this price tag.
Known issues:
0.5 second lag when using EIS. This happens from time to time, especially when tweaking parameters.
Lens switching is horrible. Do not switch lens mid-shot.
Does not support HDR.
No LUT support.
If the shutter speed is locked, the app won't vary ISO to maintain exposure.
My take for Nitrate: Impressive. The price is on the high side, and I want to adjust some parameters above 100, which is not possible.
The results are very good for me. I have a plan to shoot more interesting and colorful objects. I will try other films also.
I chose GoPro 10 because I have 9, and I know it supports flat profile. I believe choosing other cameras with a flat profile will give good results too.