I absolutely love mine. Especially in the winter when everyone is tracking in mud/salt.
Pros: Easy to use. Just need water. Gets more junk off the floor than you would think is there. Just rinse the pads out in the sink and then toss them in the laundry.
Features to look for: The triangular head (mine came with both the big rectangle and the triangle) because it works well for corners, around the toilet, etc. I also have the one that you can flip over. This is especially nice because I can do everything by flipping it and using both sides of the pad.
Cons: Worrying about possibly damaging the floors
We have damaged/crappy wood floors so I had no concerns using the steam mop on them. We have tile in the bathrooms and around the fireplaces.
We're almost done renovating our kitchen and two other rooms and are installing cork laminate flooring. I've actually been disappointed for a while now thinking about how I'm going to clean the floors without my steam mop.
We also have laminate flooring upstairs in the bedrooms, but I've never tried steaming it since I'm too worried about ruining it. Fortunately, no one ever wears shoes up there and it really doesn't get dirty enough to need it.
I'll be interested to read what floors others use theirs on, but thus far I've been too paranoid to try it.