[lawgolfer]

If your display cases, together with their expected contents, will have a total weight exceeding 50 lbs you would be wise to open up the sheetrock and reinforce the mounting area with 2 X 6's run horizontally between the metal studs. You attach the 2 X 6's at their ends with screws through the metal studs. If you work carefully, you will not have to repair the sheetrock you will have cut out as the opening will be covered by your display case or wall cabinet.

Metal studs will support vertical loads. They will not support a heavy load whose center of gravity is away from the vertical plane of the wall i.e. a wall cabinet filled with china and glassware.