The heavy-duty, hardware-mounted gate purpose-built to guard the most dangerous spot in the house.
For the top of a staircase, this is the gate we'd trust. It's aluminum, bolts firmly into the wall or banister, has no bottom bar to trip on, and swings only away from the stairs so it can't open over the drop, exactly the kind of setup CPSC recommends for stair tops. Installation is the price you pay: it takes real mounting, and banister posts may need an accessory kit. It's overkill and overpriced for a low-stakes doorway, so save it for the stairs and use cheaper gates elsewhere.