Publix; there are several surrounding WDW and all are great. The chain is employee owned and operated and always rates near the top of Consumer Reports list of grocery chains. Note that I was surprised that they beat out both Walmart and Costco for the cheapest price on a standard basket of groceries in the 2018 Unofficial Guide. There are a couple of Publix store brand supplies that we regularly stock up on and bring home (we have 6 rolls of the HD Aluminum Foil in the pantry, and I'll probably still buy a couple more in March). So good quality, good service, good prices.
We used to also hit Whole Foods on Sand Lake for DS food intolerance, but Publix has a much expanded selection of those items now too; to the point that we found more at Publix than at Whole Paychecks!
ETA: Went back and reviewed the UG. The comparison was Publix, Super Target, Winn Dixie and Garden Grocer. Mis-remembered Winn- Dixie as WalMart. Regardless, Publix was lowest, at almost half the cost of GG and 10% less than Target.