Definitely "do the Doo," especially if you're already over at Fort Wilderness. My family and I stayed at WL last November, and we took the boat ride over to Fort Wilderness just for the Hoop De Doo show, and all of us had an amazing time (FYI, my kids were 7 and 4 at the time).
The food at the Hoop De Doo and Whispering Canyon Cafe are similar (Western, BBQ-type fare), especially if you go with the WCC skillet, but the food quality was far superior at the Hoop De Doo, at least on the two nights I can use for a comparison.
The antics at the WCC can be fun, and those bottomless milkshakes are tough to beat, but the Hoop De Doo show makes for a much better night out: it's a full show with a ton of laughter and audience participation. In fact, it may be the top dinner show WDW offers, and that's saying a lot.
Have fun deciding! (You really can't go wrong!)