I also have the $2 version and use it often. For most purposes it's fine, but when you're trying to figure out if your stem is 22 millimeters or 22..2, a little extra accuracy is nice. Harbor Freight claims their $10 model is accurate to within 0.2 millimeters but claims their $20 model is accurate to within 0.03 millimeters. I have both and can verify that the difference is clear. Of course, the $2 model can be read to within 0.1 millimeters, but I don't know if I would expect that to be an accurate reading.