I use the old fashioned T covered with carpet. My vise is a heavy machinist vise mounted on a corner of my workbench. I replaced the steel jaws with ones made from oak, and I have leather wraps and lead overlays. I made them by pouring melted lead into a flat tin, which I then cut to size and folded over the vise jaws.
I have no idea how you guys can work comfortably with your vise mounted in the center of the bench and all that $#@* in the way. The T can be moved anywhere it needs to be. by corner mounting, you have in excess of 270 degree access to your gun so you can move around it when necessary, like during carving or engraving. You can stand out away from it when trying to handle a 48" ramrod drill. The vise overhangs the table so you can stand the gun on end when filing buttplate screws and such, as well as removing breechplugs. I find most of your setups extremely limiting.
It's also been used over the years to mount driveshafts and several hundred U-joints have been replaced on it, as well as a multitude of other heavy tasks. all this fancy stuff reminds me more of "Tool Wars" and "Who's got the prettiest
studio.....er shop"