Most of those things happen regardless of UI tech, in HTML as well. That's less an argument against a particular framework, but rather an argument to not build shoddy UIs.
It is way worse than your average HTML. Again, I'm not sure if those defects are the framework faults or the UI implementation, but deleting input from field when pressing tab isn't something I encountered in any HTML interface. Loading time is also similar to a desktop 1st person shooter, not to HTML.
