Great question. Scientifically, I can't say that Uranus is "better" than any other planet or Solar System body. Neptune, for instance, is also a fascinating system, especially as someone working on modeling planetary rings.
My "preference" for Uranus simply comes from the hours and hours I've spent trying to model dynamic processes in the system. It's a truly fascinating and in some sense "rapidly" evolving system. I spent my time looking at the tiny moon Mab [1] and I could spend hours telling you about how fascinating it is. If you consider how many other moons and rings there are in the system, it's just a shame to think I might not live long enought to see the undoubtedly incredible discoveries that an orbiter would lead to.
