I travel on business and sleep in hotels fairly often. I usually need to be somewhere at a specific time in the morning, so I need an alarm that wakes me up. My experience is that hotel wake-up calls seldom work because hotel phone ringers aren’t loud enough. Similarly, the in-room hotel alarm clocks, most travel alarms, and my iPhone alarm aren’t loud enough. So I bought a Screaming Meanie (do a search) and have used it maybe six times.
Pro: Plenty loud
Con: Sort of awkward and unintuitive to use, e.g., to get wake up alarm at 6:00 you set it for 6:10. Even set to Medium, will probably wake up guests in adjacent rooms. Buttons, design, and looks are on the other end of the spectrum relative to any smart phone. Has some extra features I don’t want.
Overall: It works. The Pro outweighs the Cons.