Opinion
Disappointed is the best description. Bubble Levels are pretty good but measurements disappointing. Both Distance & Height seem to work the same. They are based on holding the iPxxx device 1.7 meters above the ground. That is 5'- 5" and doesn't allow most people the extra 2 to 3" they will need to read the screen. The "measurement" seems based on trig calculated from that height. Vertical Angles are probably accurate but a little difficult to use. It is the difficulty in holding the iPxxx device steady while trying to look at the screen camera image and scales at the same time. If you mounted your iPxxx in a tripod the app would be useful. But I could grab my tape measure, level, protractor, etc. and be done with accurate results before I could setup the iPxxx for use. Lastly, Ruler places a scale on your screen so it is limited to your screen size. And there are few things I want to lay on my screen.