I'm in the same boat. Photoshop is a no-go with their new business model. Apple seem to be heading in a bad direction. These big companies seem to be forgetting that they are providing professionals a service and we are not just dumb consumers (err, hopefully not!!)
I ended up using Photo Supreme for cataloging my photos. It is great, if a bit clunky sometimes on my mac. What I like about it is that it doesn't try and tie you into their product. All the tags you assign to the photos are stored within the exif data of the image. So, you can abandon their software and still have organised photos.
I am sure aperture is slicker, but do you really want to be tied to using apple software? I don't plan on abandoning mac to go back to PC (!) but I don't want apple telling me when I need to pay them even more money!