My advice: Keep away from street performancer and el-Fnaa
I never had problems in Morocco until I arrived in Marrakesh.
Even the taxi drivers are dishonest, unlike Fez & Meknes. I paid too much for a grande taxi ride to the hotel. After that, I was on guard.
I was so happy living up in Fez, staying in a simple riad which has a full-time staff and use of kitchen. The staff was excellent, giving me candles and Moroccan CDs to make the riad feels like Arabian nights.
A fellow traveller took the red petite taxi (Fiat Uno little car) in Fez and the taxi driver returned his jacket which he left on his taxi.
The atmosphere in Marrakesh is different from Fes.
I spent some time people watching from a cafe in Jemaa el-Fnaa to get the feel of the place, and hawkers setting up stalls for the night.
Luckily, I had a great time in the Marrakesh medina.
Some parts of Morocco has a "Malaysia" feel, esp when driving down the expressway and stopping at the service station mart.