I use it, but I haven't had the chance to try anything else beyond the "lovely" camera software I got with my XT. I really enjoy it. Recently I went on vacation and did a few family sessions. I used my husband's laptop that doesn't support Aperture to PP, and my workflow that I had thought I had perfected before getting Aperture, just using iphoto and PSCS, was terrible, and I found myself getting frustrated easily.
I mostly really like that I can adjust one photo from a set (same lighting, background, etc) and copy my adjustments to the rest of them, I haven't figured out an easier way to do that with PS than to write an action and then have to sit around to make sure to keep things flowing.