I usually have names on. Mainly because the list only shows the race order not the road positions of each driver. So I keep names on so that if I've got two drivers behind me one of whom is a race leader, I know which one to allow passed and which one to block.
I always race with names on. It helped a lot when my primary competition all had the same skin as me (barring trim color differences). Or when I'm "new" to a series and don't know anyone (e.g. OWRL). People tend to change skins much more frequently than names, too.