Hi
I've only had one hip done but have met and talked to a couple of people who had both done at once. They both seemed pleased that they'd "got it over and done with in one go".
However they did warn that recovery is more difficult and any person with both hips out of use at once will find they are more reliant on friends and family.
Recently a man in India had two hips and one knee done in one operation as well as a few other bits of work and he was up and walking within a short time.
Hopefully someone who has gone through this themselves will chip in here as well.