I am obviously no expert on buying fabric (books are my weakness), but I've always found Joann's to be more of a vanilla shop that caters to the largest crowd possible (we don't go to Hobby Lobby, so I can't comment on them). Having become more interested in my wife's hobby over the past few months, I've urged her to broaden her scope in terms of supplies. The batting that Joann's sells will get the job done, but I've seen the difference between that and Hobbs. They have a fairly decent selection of fabric, but I've seen better (meaning more diverse and interesting) selections at quilt shops and their websites. While they have a lot of Coats and Clark, my wife now swears by Presencia and Aurifil (she gave a bunch of her C&C thread to Goodwill). I've always believed that you can get a great meal with a $5 skillet, but once you use a $95 one, and see the benefits it brings to the table, so to speak, you won't want to buy the cheaper one again. When I bought my KitchenAid stand mixer almost 20 years ago, my mother shook her head and said "you have champagne tastes on a beer budget." Yet that mixer has done its job all this time and continues to do so, and I've replaced several cheap hand mixers.
Your mileage may vary.