I don't know if dislocation is even a risk with the surgical techniques used nowadays? Certainly much lower than in the past, and doing plenty of rehab will improve your results.
I can also suggest that getting it done before you become totally crippled is a good thing, as its really hard to get muscles working again once they've wasted away.
Apart from being pain-free and more mobile than I'd been in ages; it's also nice not to have people regularly asking whether I'd crashed and hurt myself, as I hobbled up the beach after a kite session!