Our experience is that the standard shirts, stuff and Rima type items are all about the same with prices about the same (depending on how good you are in standing your price ground with the vendors) however, Margot has more independent vendors with local items ( art, hand painted shirts, jewelry, etc.)
The Marigot vendor lot does appear to be down (at least in May) from previous years.
Marigot also has the fish market on Wednesday and Saturday mornings. Seafood prices look high but are in euros and kilos so do the math and then not do bad, but really fresh off the boat.