Have been going there frequently for quite few years. Nowadays it is not nearly as good,with much fewer stalls. You can still get some bargains, but no so many. Heavily frequented by foreigners, Eastern Europeans and Africans, and there is a lot of theft,mainly from the traders, but you do have to be aware of pickpockets.
OK for fruit and veg, and the meat wagon does good deals.
A complaint I have heard from sellers is the rudeness of the organisers' staff, and I have heard it myself. Also it is expensive compared to most car boots. Still worth an occasional visit, but I wouldn't go every week.