Oh ... and they have refurbed K400+ for $22.45.
I use a projector so I keep my theater quite dark. Thus, a backlit keyboard is a real big dealeo for me. If you use a TV and therefore not quite as dark a theatre maybe being backlit is no big deal. The K400+ is not as well built as the K830 but on the plus side ... it's lighter and $22.45 is a nice price!