I've recently tried Lightroom, in addition to Aperture, which has been my main pp program so far, so will just say a word or two about my impressions.
- The default color conversions from Aperture and Lightroom are surprisingly similar, to the point that it's very difficult to find any distinction.
- The adjustment tools in Lightroom are better. I've not spent a lot of time investigating the tools available in Lightroom, but not in Aperture, but for sure the whole layout is more user friendly, and invites the user to fiddle with the sliders.
-The sharpening tool in Aperture are better, to my taste. Specifically I really like the sharpening tool that is a part of the raw adjustments (there is a second "edge sharpen tool"). Having said this, it's possible to get close in Lightroom, but it seems to take a lot more work.
-The default B&W conversion in Lightroom is better, for my taste. It's difficult to quantify this, but the look is closer to film B&W, unlike Aperture's which is a bit more harsh. Again, it's possible to come close to the Lightroom look, but it takes quite a bit of work.
-Lightroom is a lot faster.
-I like the nonlinear philosophy of aperture better, because one can pretty much do anything at any time, move things around add keywords. edit, etc. In lightroom it's necessary to stop what one is doing, switch modules. More generally, I simply like the style and look of aperture better, but that may well be because I'm used to it.
-The database part of Aperture seems superior. I love smart albums, the ease of tagging photos, and the ability to create as many versions as one wants of a photo, without copying the underlying file, which I don't think is possible in Lightroom.
These differences are very minor, and I certainly wouldn't switch to Lightroom on account of its advantages, and I would miss the "database" aspects of Aperture too much. Plus, Aperture 2.0 must be close, so it's probably wise to hang on.
Finally, let me mention that there does seem to be a problem in the Aperture raw conversion, in photos with point like light sources. For example reflections off water droplets. I've attached an example. The first is Aperture's conversion, and the second from Silkypix (Lightroom produces a very similar conversion). The aperture photo is definitely just doing something wrong to my eyes, that the other converters seem to avoid. I believe this was mentioned is some comparison of converters on the web, but I can't find it at the moment.
In any case, this problem occurs on a very small minority of photos that I take, and one can always use something else for the few problematic photos. Hopefully it gets fixed in version 2.0.
Finally, could I ask what the workflow of people using, say Silkypix, or a converter that doesn't act as a database, is? I mean, it's necessary to convert every image to tiff, and this takes up 40-60MB per photo, plus the original raw? Do you guys all have terabyte hard drives? Definitely not something for people, like me, who want to keep all their stuff on a laptop.