It's one of the few universally useful items; even on no-teleport levels, you can use it to teleport dangerous monsters away from you. However, trying to teleport any of the three Riders has a 12/13 chance of teleporting them to a square adjacent to you. Attempting to teleport away the Riders' corpses will cause them to immediately revive, but will not teleport them. Teleporting one of the Riders is generally a Bad Idea, but if you are already in an unfavorable position you may wish to gamble upon that 1/13 chance by zapping an already adjacent rider or breaking a wand of teleportation.
In high density areas like Moloch's Sanctum and the Astral Plane, wands of teleportation are invaluable. You can also use them to get out of engulfing monsters such as air elementals (by zapping yourself if it's a teleport-allowed level, or zapping them from the inside on no-teleport levels only - otherwise you and the monster will be teleported together).
Breaking a wand of teleportation by applying it will teleport everything in the 3x3 area around you, which can be really useful if you're surrounded in a tight spot or just need some room to maneuver.
Wands of teleportation, along with cancellation and make invisible, will make engravings vanish. Unlike those wands, however, you can find the engraving somewhere else on the level. If you engrave-ID a vanishing wand, you can test if it's teleportation by zapping a monster or item.
Wands comprise 4% of all randomly-generated items in the main dungeon, 6% in containers, 5% on the Rogue level, and 8% in Gehennom. There is a 4.5% chance that a randomly-generated wand will be a wand of teleportation.