My husband and I registered with Williams Sonoma for our wedding registry. The whole registry process was pretty easy, but we did end up with a lot of duplicates and some items we didn't want. After the wedding we tried to exchange, and since we were exhausted and in a hurry we didn't really review the receipt closely before we left the store.
When we got home we were disappointed to see that they had given us credit for many items at the lowest sale price, where their registry policy is that they will credit you for whatever the gift giver actually paid. We had to go back to the store to straighten it out. It was quite annoying.
Further, we were buying several items with our 10% off registry completion coupon, and they only used it for about half our items, so we had to return to have that corrected as well. We had three sales associates helping us, so it's not like they were too busy or forgot.
Overall, if I could do it all again I probably would have registered somewhere else. They just seemed really shady in the end.