I had to pop in and thank everyone for this thread - I would not have considered a UWA for my trip and probably would have been pretty bummed after. It's now on my "to rent" list!
When I took this shot, my thought was to de-fish it in post for an ultra-ultra wide view. However, de-fishing would have caused me to lose too much of the left and right side so it stayed in tact.
After finding this thread earlier this year and seeing all your amazing photos, I went out and purchased a Tokina 11-16mm (hey thanks, guys, for making me go broke ). I'm still learning how to use it, , but I love that you can fit so much in the frame (and love the 2.8)