They've been having this offer (or one like it) for some time now, although I haven't kept track of the history. It was supposed to be one day only last time, and it was available for several - I took advantage of the offer myself. :)

I'm just starting to move over to P7 from P6 (which I loved), and so far I can say it's worth the effort. There's no major improvements, but my impression is that everything works a little better. So don't hang around if you're wanting to upgrade.