Wouldn't want to be without one on the mill or lathe. On the mill, counting dial turns for large parts and multiple features is a pain. On the lathe boring or turning to a stop, multiple features in a single turning or even just not having to read tiny dials is a big plus. I've used a dial indicator and micrometer stop and although they work, using a DRO is just easier and quicker. I have a 2 axis iGaging set up on the Atlas 618 I've been using for several years and it's ok, wouldn't recommend them to others though but I couldn't afford a full featured DRO when I put it on (before those cheap glass scale DROs started becoming more common). Just about to put one of those 2 axis LCD screen DROs from Shenzen DROs on my SB9.