I tried them a number of years ago.
Expensive.
Relies on pictures of your work to promote you.
People that look at Houzz are not looking for pictures of racks of equipment or fancy keypads, they want to see how nice the TV you installed looks over the fireplace.
And that gets you people calling asking if you can hang the TV they bought at Costco. And they want it done for $200 or less.
After months of next to nothing, or just TV install inquiries, I talk with my "rep" to see if there was anything we could do to get better results. I was already promoting Lutron lighting, Home Theatre and Smart Home.
They consider themselves as a way to promote your business, not as a lead generating service.
So basically expensive on line advertising, that might bring you a good lead, but probably won't.
I do think it does work well for some businesses. Renovation companies, Designers, furniture, Kitchen remodels, custom finishing's etc. But for our business, people today still do not know what we do.