If mirror appears in your buff window, then I would say no they don't stack for obvious reasons. But you would still get a benefit because you would have 2 seperate procs that have a chance to hit. So if the mirror 3 failed to proc, then mirror 1 has a chance.
I never used an item with mirror on it so I'm just making an educated guess.
It's useless. The chance to reflect a spell is way too low, and the duration way too short, to be of any use. I bought one, and have been using it on one of my maces almost nonstop for weeks, and it hasn't worked once.
Well Shrooms I would have to say it is you that is "useless" if you have as you say been using it almost nonstop for weeks without it working once. WOW Talk about hard luck. If it wasn't for bad luck you would have no luck at all :)
The reason for the cheap cost for this (30 AP), is that this effect has to first proc in combat, it then lasts for 18 seconds, then if cast upon it has a chance to reflect 5% of the spells back to the caster.
Hmm, if this actually costs ZERO AP then I am omw now to scoop one of these up. Can be very helpful for any class.
EDIT: Nice, I post then he changes the information =). Either way, these cheaper AP buys are pretty nice. Gonna be hitting up the LDoN more and more anyway.