Adobe Photoshop Lightroom is about to get a bunch more expensive. In other words, it will no longer be free. The retail price before April 30 will be $199. After April 30, it will be $299. That matches what Apple is charging for Aperture.
Since Lightroom has been free of charge up until this point, I believe that Aperture sales have been slower than would be expected. As of April 30th, when the two programs cost the same amount to purchase, I expect Aperture sales to increase, since the playing field will be leveled.
Now don’t get me wrong, I am not saying Lightroom won’t sell well, I am just saying Aperture will sell better than it has been, since it will no longer be competing against a free application.