We took a day trip to Tangiers from Tarifa last week and didn't think much of it. We had a private guide who took us all over the city and to what are considered the highlights however on reflection it wasn't worth the cost or time.
There isn't really much to see or experience. The souks are nothing special, I actually prefer wandering around many of the old towns in Spain within their narrow, meandering passageways and interesting shops. It's certainly better than battling the passageways of the souks with their persistent vendors and trying to avoid the volumes of cat faeces. The shops aren't particularly interesting, many are simple butchers or greengrocers catering for the locals although there are several touristy shops filled with overpriced tat.
Much of the city consists of a jumble of disjointed construction with no redeeming qualities. Traffic is maniacal with no semblance of rules or etiquette and after a few hours we couldn't wait to return to Spain.
Of course it all depends on the reasons for visiting Tangiers. If it's to see a particular sight then go but if it's simply to experience a different city or culture then I wouldn't bother. There really was no perceptible difference in culture, it's a very mixed population and could quite have been anywhere along the Mediterranean. I would stick to Spain, far more interesting places to visit.
Personally I wouldn't want to do all that driving and the local drivers in the South of France, particularly around Nice and in Monaco, are an absolute nightmare.
