We went the first time many, many many years ago via a smaller cat. I loved it but many on board - not so much. We made that trip a few times until we graduated to the Soualiga II, a much bigger and more powerful boat but still a rough ride over but delightful coming back. We finally graduated to flying which is a beautiful experience in itself. The landing on St.Barths can be very interesting.
I would suggest everyone should go at least once if time and finances allow but if you have any possible issues with the much dreaded mal de mer, FLY OVER. Don’t sail.
Another strong recommendation is fly from L’Esperance as opposed to from PJIA. I haven’t done that trip but I have it on very good authority it’s an easier day all around..