I went through the same process not knowing whether to get Backscatter or SRP. I wanted the best of both worlds of a flip & glassfilter of SRP. So I baught both to & have a spare system on the trip.
The SRP CY 55mm filter can be threaded onto the ring hinge door of backscatter flip or on top of the macro 10 lens. Down side is lack of vent so it needs to be "equalized" to let trapped bubble out as part of the equipment check on the decent. It can even go on the Macro mini lens, but really video lights are better. My Skill level Just Can't Handle Macro at all.
The idea of adding a small macro 10 lens is borrow from polarpro & also a member here who shot really awesome macro vids that used for the SRP official site. He used it w their system which included the marumi macro lens. But the border of that is too wide so limits the range of view. Backscatters macro 10 lens use a metal wall allowing a wider view because its thinner.
IMO the SRP Cy filter result is superior. The color correction is just so nice & subtle. It also allows more light to come through. That may be the thickness of the backscatter plastic flip filter.
With a Macro 10 lens, CY filter really gives the video a sharp edge & adds depth. Making the viewer feeling being present at the scene.
Photos above did not show the combo of Cy (SRP) + macro 10 (backscatter).
Was gonna do a review. Just busy lazy. If anyone is interested, ill do that & post more photos.
Honestly having a simplistic system really makes things easier. There are plenty of stuff to fumble around already. Taking pictures & videos takes a lot of attention away from the rest.
Having abundant light as in the shallow zone and white balance turned out to be an issue for us with the Gopro 4. Sometimes we just get a green washed out screen instead of color correction. If someone knows more, please chime in.