I share your conern. To the point where I bought LR 4. I use both but, for me, Aperture has a better interface and seems just a little bit easier to learn and use. That said, the Kelby book for LR 4 has helped me quite a bit. So far, there is not clear winner, but I feel pressure to make a choice so I can stop learning software and go back to taking and working with my picture. The way I see it, here are the advantages to LR 4:
* Both PC and Mac
* Part of Adobe's core business
* Used by more pros and serious photographers (may also be considered the industry standard for serious photographers).
Apple has a big "event" planned for tomorrow. Who knows, maybe they will surprise everybody and announce Aperture 4 along with the Mini iPad.