Based on what little I've seen, I think the Xperia might be better because of the increase in front facing buttons (hopefully mappable), larger screen, and larger battery.
The downside would be a slightly larger footprint (about half an inch longer), uses memory sticks and will likely be more costly. I'll be interested to see how much of the $799 price tag the carriers can eat.
I wonder if the Fuze (being HTC) would be more hackable?