The most famous of the old-time pier restaurants, Chaolay serves a full house nightly, even in the low-season. There's a chaotic open kitchen on the ground floor allowing you to watch the chefs and see the fish tanks. Service is quick and sharp, but you may have to wait a long time for a table, especially one over the water.
Make no mistake, the food here is delicious, but all of Hua Hin's seafood restaurants down here have pretty much the same food, quality and prices, so you can dine at one of the other places to have a quieter night and no wait for a table with a view.