Cheap eats> On the beach is Soda Piedra Mar, good food, especially fresh fish, great prices!
Sunsets> Buenos Aires restaurant is a little expensive, but great sunset views, so go for cocktails. Or, eat wood baked pizzas on the beach at Pizzaria Playa Carmen
Italian/pizza> Al Chile Viola has pizza nights on Sunday and a 'romantic' setting for great- if expensive- Italian favorites like lasagna. La Bella Napoli also serves great wood-oven baked pizzas!
Seafood> The best seafood restaurant in Mal Pais is Mary's
Also, Las Piedras - Argentianian Steak Grill - steaks, ribs, chicken cooked over an open fire.