We normally recommend a new replacement from a reputable shop such as randy's revmax suncoast. Reason being is that way you get a nice warranty and you know it's done right. i have seen a lot of customers get theirs rebuilt and when there is a warranty issue they try to get out of it or blame something that wasn't replaced. Generally you are only a couple grand away from being to get into a full replacement anyway so to me it's definitely worth the extra to do that.
Holler if you have any questions as we are happy to help and sell and install quite a few transmissions here at our shop.