Lots of variety in both takeout/ready-to-eat meals and groceries/ingredients. I've tried a bunch of different vendors here and generally been happy with everything I've tried. In particular I'm a regular customer to the bagel shop upstairs (St Urbain) and a pastry shop downstairs for croissants, strudels etc.
Gets crazy-busy on the weekends - I suggest going early! Be prepared for crowds and unless it's very early in the morning give yourself extra time to get in and make your way around the market. I haven't been during the week (it's only open during the daytime) but I imagine it's the same. I honestly don't know if the quality of the produce and other products makes the crazy crowds worthwhile but depends who you ask I guess!