I don't own a 16x but can share my experiences on using the 20x, mil-quad reticle.
I use them in 20x for open class. I actually like it enough that I have three of the 20xs, one on my open class PCP, one on my open class springer, and the third just floats around on other airguns. I have a buddy who bought the 16x and plans on using it for hunter class in the next few months.
The rear AO is a bit interesting. I have thought about putting some kind of donut on it but have yet to do so. I just applied tape to the rotating part of the ao adjustment and marked it. The lines get pretty close out past 35 yards. Realistically, (in 20x) it can range to the exact yard from 10-20 yards, within 2-3 yards from 20-30, and in 5 yards increments out past 30. When the wind isn't onery, I usually finish in the 80-90% range for targets knocked down (with the PCP).
I have seen all of the videos on the swfa's repeatability when clicking, but I started in Hunter class and, even though I can click in Open, just use holdover. The mil-quad reticle is awesome for that.
It works well enough for me, that I don't currently have any plans to replace it. It is light, pretty clear, snaps in and out of focus repeatedly (and it doesnt care which way I am rotating, near to far or far to near to land on the same mark).
For perspective, I went from UTG and Vortex Crossfire type scopes to the SWFA. If you're looking for something in the $300 range, I think you'll be pretty happy. If you're a Schmitt & B$nd$r type of guy, you'll probably be unimpressed.