I hired Shadyside House Cleaning to clean my apartment before moving out, and confirmed our 2:00 appointment the day before.
The day of, I didn't hear from them, and called around 2:15. Jose said he'd be there soon, and after a few more calls he showed up around 3:45.
He estimated it would take 2-3 hours to clean my (completely empty) one bedroom apartment, but it ended up taking over 4 (which is fine, but again he didn't keep me updated, so I kept having to text to see what was going on).
They did do a fairly thorough job, though, and the apartment looked great when they were finished.