I really like iGaging's dials and calipers, but I was a little disappointed by two specific drawbacks of the double square set. First, the head doesn't slide smoothly at all. That might not be fair because I'm comparing it to my combined Starrett square, but I expect it to slip because you're doing that to it all day. Second, the markings on the rulers are very dull. I find it difficult to read them in any light other than the best. I went ahead and bought a Starrett 13A and it's better on both counts. Otherwise it's well made and I wouldn't say it's a bad tool, just not useful to me.