I used Aperture 2 for about 6 months before dumping it for LR2. The editing capabilities of LR2 blew Aperture 2 out of the water, especially localized edits. I now have a massive LR2 library and I refuse to switch back to Aperture now that they've caught up with LR. If I switched every time a new Aperture or LR was released, I'd probably go crazy