I looooooove my Prius.
The SmartKey is the coolest thing in the world

! You can just have the key in your purse and walk up to the car. When you put your hand on the handle, the car unlocks - don't have to take the key out, don't have to put it in the door, don't have to click it. Then you can just start the car (if you have the key) by pressing the brake pedal down and pushing the Power button on the dashboard.
One thing to be careful of...let's say you go out in the morning and start the car and then go back in your house and then you get in your car(but leave the key in the house). It is possible to run the car without the SmartKey on you. Just make sure you check & the car/key icon isn't flashing yellow - that tells you your car is running but the key isn't in the car.
If your car is going to sit for a week or two(say, you'll be at WDW

), you can disable the SmartKey feature, which is easy to do. The way it was explained to me is that the car is always searching for the SmartKey & even though that isn't a lot of energy, it does add up. So if the car is left for a long while, the battery could possibly drain.
It's a great car - you will love it.
agnes!