The $20 deal on Rapture is too good to pass on, but then I noticed that the latest update seem to date back to 2010.
As a matter of fact, Rapture (for Mac at least) is now 2 major OS revisions behind - no support for Lion or the more recent Mountain Lion.
$20 is no big deal, and I'm still running Snow Leopard, meaning that I should be able to use Rapture. But, I'll upgrade my OS sooner or later, and, even just out of principle, I'd hate to waste money on a product which isn't being developed/supported anymore.