Not very good at all!!
Hochtief are currently working on J16 of the M4 which is by my house. The other day they were cutting metal and spraying sparks all over cars driving past. Then we had a foggy day and one of their lorries came flying out of the site with no lights on a stopped across both lanes of the road causing everyone to make an emergency stop. Just recently I saw one of their large tipper lorries come out of the site with the back still up in the air, very dangerous, nearly caused an accident.
This week they managed to break the local gas main on the north side, which meant we were all evacuated and were not allowed back to our homes, there were road blocks to stop us. It is still leaking gas a week later. This lead to them banging on doors asking people if the knew where the gas main went on the south side because they had no idea. Then they kept driving slowly up and down our road which creeped us all out and made us feel very uncomfortable. My guess is the company is run by Forest Gump.
They have also managed to cut down all the trees and hedges around us, I asked if they were going to put them back and they replied "NO".
So, if I were to review them I would say they were pretty incompetent, have no regard for health and safety and they take delight in destroying the environment and making everyone's lives a misery. Don't do business with them for your own sake. They are just corporate monsters.