I have 3 leg vices I use. -different sizes, in different locations. My "portable" one is a small one with the leg folded upwards so I could mout it onto a hemlock stump that held my anvil- travelling forge set up.
I like leg vices because the are made by forging, not cast and are super tough. I could use a sledge on one, dent it and it would still work. They are all used and probably over a 100 years old. 25 was the most I paid. -also called blacksmiths vice. - If you see casting marks and casting rough edges- it is going to be brittle- don't hit it with a hammer. -Learned the hard way.