We don’t often write about local hotel buffets because most of them tend to be large and sacrifice quality in favor of quantity. In fact, some of the worst food we’ve eaten at any restaurants in the Sukhumvit area have been at hotel buffets — expensive hotel buffets, at that.
However, here at Peppermills in the Amari Boulevard Hotel on Soi 5 they’ve taken a simpler approach and eschewed many of the offerings that other hotels add to their buffets to justify raising their prices. There’s no elaborate carving station, for example, but they did have a roast of pork when we were there recently. And they do have sushi but it’s not  a large selection, just enough so that you can find something to go with the fresh wasabi on hand which is sushi’s main reason for existing anyway.
There are a number of reasonably well done hot main dishes and also two mushroom soups — one a spicy Thai version with enoki mushrooms and one a creamy western-style — that were both quite tasty.
With a price tag of 683 baht net the Peppermill’s buffet isn’t the cheapest around nor is it the most expensive. It was just right for us as far as price and selection and value for money, the most important factor of all. 
Peppermill, Soi 5, 02-255-2930