It highly, highly depends on the facility, their policies and how they train their employees. I've worked in two great places and another one that made me want to tear my hair out (I left after only two months there).
The second one was pretty poorly run all around. I could've gotten free boarding, but when I went out of town I ended up leaving him with my coworker instead. She took him to work with her but spent the nights with her. Once she quit, I would've been uncomfortable having him there at all.
I really like the one I'm at now and have already boarded him a few nights. He goes with me to work and if I could afford it, I would have no hesitations about taking him on my days off, too.
Really, daycare is great for some dogs and horrible for others. Very few BCs seem to do well at daycare because it's not the kind of stimulation they need and there's just too much going on and they get frazzled. Generalization, of course - but just an example. It's not a perfect system, but for some dogs it works very well.