I have not had the expectation here to purchase a professional device, but for me as a "hobby" -Heimwerker it is great and a must-have. Measures very accurately, I would never hammer out better with a ruler by repeatedly applying.
- No surface measurement, very narrow contact surface, thereby sometimes "shaky" if you want to measure 90 ° angle
+ Very accurate
+ Very fast
+ Simple operation, works immediately
+ Very inexpensive
+ Real laser measurement, no ultrasound
Conclusion: If you want to use the unit professionally is wrong here. Who needs a handyman should necessarily strike. Price / performance is hard to beat