... since you mention straightening.... Imagine you have to straighten a series of 5 or 10 or whatever number of pictures. AutoSync in Lightroom means I straighten one and they're all done - nothing more to do. Meanwhile in Aperture that's 5 or 6 clicks lift and stamp, isn't it?
Well, you can use keyboard shortcuts so you can lift adjustments, and then stamp the adjustments, so we're talking a couple clicks and a key combination. But true, Aperture does not have Auto-Sync. That said, about 50% of the time I use Auto-Sync I end up doing something REALLY BAD in that I apply an adjustment to a bunch of photos that I REALLY DIDN'T want to apply.
There are a few things I'll freely admit that Lightroom does better (or exclusively) right now:
* Sharpening overall is better. You have more control, and can get better results
* I still like the targeted adjustment tool and how you can use it to operate on the photo itself
* The basic adjustments are better. Whites, blacks, shadows, highlights in LR have more control and give better results
* The gradient tool in LR is great, and there's no equivalent in Aperture. It gives great results for a lot of exposure balancing.
* Lens corrections and auto CA removal. I shoot a number of wide angle landscapes that have curved horizons and this is KILLER
* LR's clarity tool can do more with better results than Aperture's "definition" equivalent can
I find Aperture's file management better (it is more flexible, period), and I tend to get better initial renders with Aperture than I do with LR with the "defaults." I can get good results with LR but it's more work. Aperture does a very, very good job with the defaults, and the "auto" setting that came in with Aperture 3.3 is simply fantastic. The skin-tone based white balance is also incredibly useful. I had to work through 1000 shots of kids playing baseball in a grassy field and there was nary a grey thing in the scene to balance on; using skin tones for this is pretty great (now given they were all in sun I could have fudged and struggled for 5 minutes in LR to get the WB right in one, and then used Auto-Sync to do the rest, but I digress