I recently upgraded from 12.04 to 13.04 (through 12.10). I have re-enabled workspaces in Appearances/Compiz, have a workspace-switcher launcher icon, and can expo with Super-s. The keyboard shortcuts tab lists Ctrl-Alt-Arrows as the workspace switch shortcuts, but those hot-key combinations don't actually switch my workspaces.
Potentially related: the workspace switcher launcher icon does not accurately reflect windows that are open in workspaces; there is a default-looking two window image that follows the workspace that I'm in regardless of the existence of windows in that or other workspaces. I don't especially care about this functionality, but if it is supposed to be working and isn't, it might stem from the same problem.