As usual, the guy starting the semantics flame doesn't have any convincing arguments. I think the brands the OP mentioned would typically be classified as upscale (upper upscale in case of Sheraton and Hilton), premium, or full-service. The term "mid-range" for these brands is rather uncommon. Mid-range (more typically: midscale) would refer to something such as Hampton, Tru, Mercure, Tryp, HIX, etc.