I purchased this Restoration Hardware 36" Hutton vanity and had it in a guest bathroom that was used mostly as a powder room on a fairly regular basis. The vanity was beautiful and the marble top was thick and gorgeous and honed instead of the typical polished. Unfortunately within a few months the doors warped even though we never showered in the room and maybe bathed in the tub once a week at most. Restoration Hardware was good about sending repair people and replacement doors, but even the replacement doors were warped. If I set the doors on a flat surface, they wouldn't lay flat. The repair people they sent (local companies) were frustratingly incompetent. The frame was constructed nicely but the doors were a big problem.

For another bathroom we purchased this Water Creation Madison 60" vanity but we only used it for a few months before we sold the house. It seemed only slight less well constructed and was significantly less expensive than the 72" RH version. We could only fit a 60" so the RH option was out anyway. The marble was a nice solid piece and equally thick, but it was polished which I liked less.

Overall I felt like the Restoration Hardware vanity was only slightly better quality than the Water Creation vanity. When I've looked at Pottery Barn vanities in the stores, I have been less impressed with their marble tops which seemed to be thin. Hope that helps some.