I was there in December 2019. Stayed a week all inclusive in a 4* in Mahdia for £350 which was a bargain. Before i booked i thought of that terrorist incident and put things into perspective that the odds of getting killed in an accident on the M60 going to the airport are probably lower than another terrorist incident happening again.
Most of the hotels there are big and tend to be 4 or 5* rated, and the staff go out of their way to keep guests happy and entertained. I went on twice on trains to Sousse Hammamet and Port El Kantaoui which i enjoyed, especially Port El Kantaoui as the harbour is lovely with it's pretty white buildings and palm trees overlooking a nice harbour amongst several cafes and restaurants. I ate out twice and the food was good and similar to Turkish food.
Most people i met were friendly and welcoming and it's a shame that that terrorist incident stops holidaymakers from going there. I will go there again and probably choose Port El Kantaoui to stay at.