I've owned a PLS 3 and loved it. Never had any trouble with it. Never
dreamed when I bought it all the uses I would think of for it. Used
it for everything from setting beams level to marking out top and
bottom plates for interior partitions to plumbing trusses. Also owned
a Robotoolz similar unit. peice of junk. It was not reliable--tried to
get the company to fix it, but that just ended in frustration.

I also used a PLS 5 a which shoots two beams at 90 degrees. Didn't
find that feature real useful, since you still have to transfer the
beam down. thought it was just as fast to use traditional methods like
3-4-5 or calculated diagonals. Good quality tool though.