I recently worked on a system with Audyssey DSX wide and height Channels. As I mentioned in a previous post the height channels work very well. The wide channels were a different story. Comparing the sound field with this feature active and inactive was very different and the wide speakers added an unnatural character to the sound. I do not recommend adding these channels to a surround system. I believe you would be much better off spacing the front channels wider if you want this effect than adding these additional speakers. The wide channels also seemed to throw off the channel level balance when active.
It should be noted that the wide channels in this application were high quality along with the other speakers in the surround system. The height channels were much smaller and less expensive. The front speakers were already in a typical position and the wide speakers were positioned about 3 ft further out. The room was also very good acoustically.