Each Dixie location has its own feel and style but the basic show elements are essentiall the same. If there are any major changes to the show, they usually occur in January when the show transitions back to the regular show after Christmas.
That being said, the show in Myrtle Beach has some differences from the show in Orlando. Last I heard, Myrtle Beach was still doing the BBQ scene (one of my faves) which has been replaced in Orlando by the "Home Cookin" (barf) scene. Now this may have changed - I haven't spoken with anyone at the Myrtle Beach location for a while.
Other differences are that the Orlando location serves beer and wine and has very slightly toned down the "Rah Rah Americans rule" message to better appeal to the more international guest base found in Orlando.