If you are looking for a clean, quiet, modern, hotel that is conveniently located near the train I highly recommend Casa 400. I stayed there while working a trade show at RAI. It is a 3 minute walk from the hotel to the Amstel Station and then it is 3 stops to RAI...making it at most a 15 minute commute. There were no fears of not getting on a trolley or bus because it is full and having to wait for the next one as you might find if you are in some of the more interesting smaller neighborhoods not on the train line.
Casa 400 does not sit within walking distance of a large concentration of quirky restaurants, pubs, museums or other tourist stuff. It is all accessible by the train, taxi...never more than a 3 minute wait when called by the front desk... or if you want, bicycle... which the hotel will happily rent you. Instead this is much more of a business persons hotel. There is free wi-fi all over the hotel, a rather large computer/business center in the lobby, and rooms have plenty of desk space with accessible power outlets (my one complaint is there are no built in USB ports which many modern hotels are now doing at desk areas to make recharging foreigner's phones simple and not requiring a European power adapter).
By American standards the rooms are a little small but beds are comfortable. The bathroom was clean and there was plenty of hot water. As a business traveler I would have liked an in-room iron rather than needing to request one. Closet space was large and the in room safe was big enough to hold my 15" mac book pro.
As for food I only had the breakfast buffet. It was exactly what I expected...some cheese, some meats, some vegetables, yogurt, cereal, fresh fruit, scrambled eggs, bacon and sausage on a warmer and a selection of breads. It wasn't like the international buffets you get in the Western Hotels in Asia. It was a little expensive for what you received if you did not have the buffet included in your room price, however there was no real alternative within a 5 minute walk of the hotel unless you wanted fast food at the train station.