Appcelerator... kind of sucks. But it's much better than HTML5. It performs much better than HTML5, but I find it very hard to write. There's just way too much quirkiness and hacks to make it work. The only thing I like about it is that it's written in JavaScript (but it would be fun to learn a new one).
Performance-wise Qt is quite good, but still comes up a bit short on the Widget quality and consistency side - this is where project like my native component-wrappers come in to the story (shameless plug - http://achipa.blogspot.com/2014/11/qml-wrappers-for-native-a...). The good news is that you can still keep on the JSON/Javascript side for all of this, regardless of whether you use custom UIs, use Qt Quick Controls or something else.
Long story short - it's not quite an Appcelerator replacement just yet, but certainly keep an eye on it! :)
Appcelerator... kind of sucks. But it's much better than HTML5. It performs much better than HTML5, but I find it very hard to write. There's just way too much quirkiness and hacks to make it work. The only thing I like about it is that it's written in JavaScript (but it would be fun to learn a new one).
How does QT compare in this regard?