At work we've got dual monitors mounted to each desk. I ordered docks for my group, mostly because I was tired of having to carry my dock around each morning. (Hot desking ... don't get me started.)

The windows lappers work fine. Macs will either use one in extended mode, or both if you duplicate the main screen to both. It drives both just fine if you put the second in the HDMI. So no dock love for Mac users.