Incredibly useful and accurate for setting levels and perfect verticals.
This is a good price for a laser level. It's the second one I've bought (the first got "borrowed" and I was lost without it). It's incredibly easy to use, just put it on something stable or solid using the pivoting clamp and point it. I just use an old camera tripod, which makes it easy to position and is portable. It sets itself up and gives a good bright horizontal and vertical line. Batteries last a long time in it.
It's far more accurate than "is the bubble in the middle?" and, in accuracy, as good as using water levels over a large distance but without the hassle. It's also very easy to match a height with a level because it can so easily be adjusted to that level. And no pencil lines or marks needed because if you want to leave a job and have a reference point, you can come back to it any time later and just point the line at the reference point and you know for certain that it's exactly the same line as you used before. Try doing that with a bubble!
Anybody want to buy a bubble? Only one previous owner, guaranteed to float.