Like aardvark, I've found it to be pretty damned convenient. The key fob never has to come out of my pocket. I walk up to my car, open the door and it recognizes the proximity of my fob so it unlocks upon touching it (not sure if Renegade is equipped like that, but that's how it works on my other car). Not only that, but as soon as I'm next to the car, it recognizes me and turns on the vanity light in the car. Nice touch.
Starting the car is just like with a key, except you're just pushing a button.
The only thing I had to get used to was the audible alert when I would leave my car running and I step outside of the vehicle. It recognized that the fob was exiting the vehicle and it tries to warn you that you might want to leave the fob if someone else is going to be taking the car (like a valet, for example). It's easy to forget since it's always in your pocket. Not a big deal, your car will continue to run without the fob, but it won't be able to start up again without it.
That all said, I'll never go back to a keyed car again. It's damned convenient, and you don't end up with all those scratches around the door lock/ignition. Even if the battery on the fob dies out, there's a manual override, so you'll never be stranded somewhere so long as you have the fob.