You are probably thinking of the Boston Harbor Hotel, on Atlantic Avenue. I haven't stayed there but have been to the restaurant and the bar; I've stayed at the 4 Seasons.

The Boston Harbor Hotel is in a good location for the downtown financial district, the Quincy market area, the North End, and for access to the airport. As the name implies, it's on the harbor, and east-facing rooms have a good view of the harbor and the airport. If the Boston Harbor Hotel isn't quite in the class of the Four Seasons, it's certainly close.

The Four Seasons has a fantastic location across from the Boston Public Gardens, one of the country's nicest urban parks. The Four Seasons is also well-located for shopping on Newbury St, walks in the Beacon Hill area, the Theatre district, and many of the city's best restaurants.

It is no hardship to stay at either location; if you were visiting Boston twice I'd recommend trying each of them once. Overall, though, I'd give the edge to the Four Seasons based on consistently good service and access to the most interesting parts of Boston.