There have been a number of Flexshooter threads on the forums, you might try entering Flexshooter into the Search box on top of the page.
Here's some of those threads:
I recently learned about the Flexshooter Pro tripod head, which supposedly provides similar functions as both gimbal and ball heads, in a very small package. I watched an online demonstration of someone using the Flexshooter Pro with a Nikon D850 and 600mm f4 lens, and it seemed to work smoothly...
bcgforums.com
For the last three or four years, I have been using a RRS BH-40 primarily for landscapes. I love everything about it but I want to add a leveling base to make panoramas easier. Within the last year or so, I have been getting into the wildlife side. Target subjects tend to be Mountain Goats...
bcgforums.com
I'm going on some bird trips this year and need help choosing the best travel tripod with lightweight gimbal head set up for my Sony A1 with 200-600. Closer to home I use a monopod and Wimberly head. I have a fine RRS tripod with gimbal head - but it's too heavy to carry more than a short...
bcgforums.com
That said, I picked up a Flexshooter Pro a while ago and after several decades shooting full sized Wimberly gimbal mounts I sold my WH-200 as I find the Flexshooter gets the job done in a much more compact package that's easier to deal with when traveling.
Flexshooter Pros:
- Smaller, more compact and provides the same constrained pan and tilt with no risk of lateral ballhead flop just like a gimbal head
- Built in leveling base (outer ball)
Flexshooter Cons:
- A bit more friction when panning or tilting compared to a well balanced gimbal head though I find I can still pan and tilt with a light 'one finger' touch
- More limited for extreme up or down angle tilts compared to a good gimbal head
In my experience the Flexshooter Pro is great for use with heavy long lenses like the 500mm and 600mm f/4 lenses and decent with some smaller lenses but by the time I get down to something like the 500mm PF with a Z6/Z7/Z8 style camera body I find the Flexshooter Pro is a bit stiff for such a light setup. The Flexshooter Mini is probably more suitable for lighter and smaller camera and lens setups but I have no hands on experience with the mini version.