5 stars for courteous, professional service with good communication, and all out effort.
3 stars for moving technique.
2 out of 3 pieces ended up with not-insignificant markings / abrasions on them. The damage was sustained likely as a result of getting 'stuck' in the stairwell, as well as moving the furniture on the concrete without a moving blanket underneath. The sofa in particular was quite heavy, as it had two recliners built into it. However, it had been moved 3 times prior without sustaining any significant damage to the leather.
These guys have the strength to get the job done, but they need to do a little homework on how to move difficult, heavy pieces in a safe manner. They will save their backs and your furniture if they spend a little more time thinking things through rather than just trying to muscle it, which doesn't always work with big, heavy pieces.
In the end, I would consider hiring them again, with the caveat that they have studied up on various moving techniques to minimize damage.