Do not pay to see the Great Mosque unless you're really interested in peering over wooden barricades and ropes into the unlit, windowless prayer room. Non-Muslims are only allowed into the courtyard . This would only be good value if you were really interested in all of them and came equipped with a deep appreciation. We only took one louage, from Sousse to Hammamet. Time really is money for a louage driver, and they aim to get where they're going as fast as they possibly can.
Every road is an autobahn for a louage driver.
That said, the louage we took was relatively comfortable. Louages always seem to be white Peugeot station wagons with a red stripe down the side. Absolutely nothing, as far as we could tell. The only police on the roads seemed to be officers directing traffic, or standing outside tiny huts at roundabouts. We never saw a police car that wasn't parked in front of a police station.