I have two patternmakers vises that I have been using for many years. To me, these vises are so versatile that it seems a shame to commit them to just one location. Instead of doing so, I've adapted my work stations to accept them as needed. I've also added length to the mounting screw so that I can mount them to thicker bench locations. One picture shows both vises; one mounted on my stocking horse and one mounted on my work bench. That one one on the workbench works alone or in tandem with my Versa-Vise knock-off from Woodcraft. The portable carving bench is my latest iteration using the vise I normally have on the workbench.
If looking for the one best location though, consider an end corner of the bench that allows you to work freely on either side of the vise. You might also consider designing a stable mount such as an extended arm/island that takes it away from the bench a bit so that you can easily get to both sides of the vise while working.
Another thing I've done and seen others mention as well is to cut the knob off the clamping handle so that I can get closer to the vise while working. I got tired of it poking me in the gut all the time. While it is a bit slower to clamp, there is still plenty of leverage to clamp with just the crosspiece.