Peterg,
I know what you mean about living on this site.. it's becoming addictive. Try downloading the manual - it'll take your mind off the car, although it does tend to drive you crazy trying to imagine you are sitting in your hypothetical car and fiddling with the settings.
About the self parking thing - we have had it on 2 Prius's and haven't used it once in about 7 or 8 years. The dealer demonstrated it on the first car and I noticed that even he parked in a bay with no cars within 50 feet. I share your worries ! And, as the manual says in large letters, you are in control of the vehicle... The rear view camera is good though - when a young lady backed out of the bay next to the one I was backing into, I saw the front nearside wing of her car quite clearly as it clouted the rear valance on our car.
I do like the idea of adaptive cruise control, blind spot warnings, and all the other safety features - particularly the speed limit sign repeater. Oh, and the spare wheel for reasons stated elsewhere in the forum.
Ian