My wife gets off very quickly with the magic wand. It is very powerful even on low. I find that when she uses it too much, it makes her less sensitive and therefore it is more difficult to orgasm without it.
It is too loud to use when the kids are in the house.
I bought a Form 2. It is also quite powerful (not as much as the magic wand) and also quite quiet. I like that it doesn't have a cord and is rechargeable. Another plus is that it is water proof.
I bought one for my wife after reading lots of positive reviews. She used it twice....and both times, it was way too intense. It is under our bed collecting dust right now....while she continues to use a simple $20 dollar, plain-jane battery powered vibrator. That one makes her happy.