Yes I know about the balancing, and I saw it on their website that is not the issue, but since I change filters and often need to do it in the field, it is not an exact science, in reality just a penny on the back does not properly balance it as the balance is affected on two axis, that complicates it if you want to do it right. So in general I prefer to use the screw on filters because they do not add so much weight and do not need balancing. The SRP filters are not any different optically, my main interest was the grad filter which like I stated I am not convinced really works as advertised. I often shoot late in the day when it becomes necessary to change filters to different values to maintain the video frame rate. Or if I am shooting stills, I only use the UV filter and I get the best image quality with the higher shutter. So it is all a matter of what works and what is practical. The appeal of the SRP is that they slip on but it often takes me longer to get them on correctly and or remove it, than to unscrew and replace with a different filter.
All opinions and experience, just related mine and my reasoning, not stating that anything else voiced by others is wrong, just there are choices and options.
Alan