As a former professor I was once (only a couple years ago) assigned a classroom with a chalkboard and it was easily the worst semester. They look nice when they are clean, but as soon as you erase something it ends up being unreadable.
Not to mention I would end up covered in chalk at the end of a lecture.
Depends on what chalk you use. If you use chalk from chalk (CaCO3), then yes, it's awful, but if you use chalk from gypsum (CaSO4 hydrate), it's readable on a wet board and erases well.
A chalkboard pro-tip (suggested by a former colleague years ago) - get some of the foot-long "janitorial" erasers. We have them in every classroom. They erase very quickly, and pretty cleanly as well.
[We also have projectors, document cams, and touchscreens (which I think are Cintiqs) in each room for people who prefer them. I think only one room has a whiteboard/smartboard.]