Decided to build my own house and reached the stage of mounting the stairs. Prior to that, he worked for a construction company and collected the roof. Actually in the process of work and found this service, regularly used it and almost no problems. Stairs are not my profile, to see for myself couldn't, but figured there stocks was not, so there will not be.
Brought intended the calculation to a friend for testing, he said that everything is in order, well calculated, but not perfect and saw a few fixed numbers. As he said, math is good but experience is better.
For a month everything was cut and collected. If not sick, then faster.
As you can see, the program works well, says the same is true, as the roof and the stairs. Don't be afraid to use it!