Yeah - hands down this is a tactical edge type device with its one hour CD (it also has a 30-60 second CD upon equipping it so its something you need to plan for).
Additionally, when you use it, just like mage invisibility, you can't see anyone else either, meaning that you'd best make a note of where the mobs are or you'll go visible in the middle of them.
Finally, it does require 200 skill to use it so don't buy one if you aren't an engineer.
Despite those limitations, its saved me some greif on a number of occassions so I always keep on in my bag along with my old parachute cloak too.