I think it's a case by case basis, or at least it has been in my experience. I typically would always leave v-sync off both when these were new and displaying on a CRT as well on a retro build in the mid 2000's on an LCD. I know horizontal artifacts akin to tearing have been reported running without v-sync but I either never noticed them or they didn't crop up for me. The mouse lag with v-sync on was a major issue for me though and that was the deciding factor. A modern display and ever aging hardware may change all of this however.

I prefer to leave it off. Some scan-line artifacts will be visible when hitting high framerates, but its preferable to laggy controls.