Four stars may be a bit generous, but they deserve more than three because all of the hard stuff turned out beautifully -- slate roof, bluestone walk, concrete sides of house, and pool tiles.
They know nothing about wood and do not protect it. Before I hired them I emailed them my worry that untreated teak may be an issue. They said it would be fine which I incorrectly took to mean they knew how to protect it. They bleached out all of my wood door frames, doors, and window frames, which now need to be reconditioned with linseed oil to restore the stripped oils. They will now always look more weathered than their years.
I complained about it after the cleaning, and they were coming back anyway to catch some missed spots and clean my pool. After the redo, while the wood was still wet, they pointed out how nice it looked, dark and shiny, and claimed it had retained all of the oils. I am not stupid. I knew it would dry out looking bleached again, that if you do the same thing you get the same result. I found that statement to be obviously false and not respectful of my intelligence.