I was in Casa, Tangier, Fes, Chefchauoen, Meknes and Rabat during the spring of 2011 (shortly before the Djema el Fna explosion) and although we saw several protests (it was the height of the Arab Spring), never felt at all threatened.

Two separate groups of friends--who could be described as high-maintenance travelers--were in Morocco (including Marrakech) this spring/early summer for the first time and all raved about it. None gave any indicate of feeling unsafe.

Here's the US State Department's travel information on Morocco.

I would travel there tomorrow if I could.