I got my cat declawed (front paws only) when she was a kitten as a safety measure for my son, who was not quite one at the time. Ally did not display in any way that she was in pain, and she is the most loving, affectionate cat that we joke that she thinks she is a dog. It did not alter her personality in any way. She has only ever once snuck outside, as she hates to be away from us, and when she did, as soon as she discovered she was closed out of the house, she was meowing at the door to be let back in.
I think if it was such a horrible thing to do, it WOULD be illegal here, and it is not. I love my pets very much and would not do something to them I thought was cruel. I find it more cruel to leave a cat just wandering around outside to take care of itself all day.
I have posted this same thing on another thread though and got flamed, but I think it is a personal decision to make. I don't think it is any worse than getting your pet "fixed". As a matter of fact, there are probably a lot of cats that end up in shelters because of scratching problems that would not be there if they were declawed.