I didn't notice a difference in the sensation of my *bladder,* though as others have said, the experience of actually peeing is (of course) quite different. That said, I asked my wife out of curiosity, and a friend and HER wife, and the consensus is that all four of us feel that "forward pressure" on the bladder... and two of the four were born with vaginas. So I'm not sure if the bladder sensation necessarily indicates much about the anatomy much lower down.
I did find out that the female urethra is about 3 inches long, so the urine has a lot less distance to travel. 🙂 No wonder it's easier to get a bladder infection after GRS, too, since I guess bacteria only have to travel that distance back UP!