If I could only have one vise, it would be a leg vise. I have 3 set up in my metal shop, a 3" is my main filing vise. A 5" is on a post near the forge, and a 7" is there if I need it. The 7" is great for removing breech plugs. All have smooth jaws. The jaws will conform to non-parralell objects. I have 3 machinist' vices in there ,too. One of them has smooth jaws. I do not like teeth on a vise.
Pay attention to what you're buying. The one mounted to the post above is missing the mounting plate. The one mounted to the bench is complete. In addition to fastening the vise down, the mounting plate secures the spring. If this isn't tight, the handle will fall down when it isn't tensioning the jaws.
I would only pay $200 for one in VERY good condition.
It is interesting how the threads were made on some of these vises. Some have threads that were cut on a lathe. Earlier ones have threads made from two pieces of square stock that was wrapped around the shank of the screw. These pieces were then unscrewed from each other. One piece brazed to the screw, the other piece brazed inside the nut, making mated threads. I have 2 vises made like this.