Looks nice. But then Jenkins is an extremely low bar to jump. I've always considered it kind of hilariously bad and at this point it would be kind of sad to see it improve ... it just wouldn't feel like Jenkins any more!
I'm pretty fond of Bamboo's default (only?) theme [1].
Although the focus on building Java software is undeniable, we build a bunch of C# projects on it just fine (with its built-in MSBuild and MSTest tasks).
Bamboo 5 brings "deployment projects" [2] which makes CI just that little bit easier.
I've also used Hudson (ages ago: prior to it being forked) and although it's not a fair comparison, Bamboo is miles ahead.