I put one on a
B7100 (gear) approx 29 years ago. I believe it was a Danuser, not sure if it's even still made. Worked a hydraulic motor (off the FEL hydraulic pump) which engaged the 350# weight column with a friction rubber wheel to raise it, then drop. Pretty effective, drove a post so tight that sometimes I couldn't pull it out with the FEL.
The cons were several:
!. The
B7100 is a pretty small tractor to be hauling an attachment that heavy and TALL (it occasionally got pretty scary in hilly terrain).
2. The soil out here varies a great deal from extremely hard, (hard pan) to glacial till liberally laced with various size rocks which all conspire to deflect the post out of plumb.
3. As I recall, I had to modify the post drivers attachment system considerably to allow more and easier adjustment to plumb the driver on hilly terrain.
4. It was a bit nerve wracking to hook up and unhook and store because of the overall weight and top heavy nature of the beast.
5. For better or worse, it wouldn't work in the rain, because the lifting "tire" would slip on the weight column.
6. I don't think I ever drove a steel "T" post with it because by the time I could have it aligned to start driving, I could have driven two or three steels by hand.
Other than that, I loved it

We installed lots of fences together.
Although, if I had it to do over, I might seriously consider other options.
Hope that helps
Regards
Sherweld