Well, you can bring in the raw file (without edits), and you can bring in a rendered RGB file (e.g. jpeg or tiff) with edits baked in, but what you CAN'T do is bring in a raw file, with the non-destructive Aperture edits, and have Lr translate those Aperture edits into Lightroom edits.
Put another way: no raw converter/editor can understand the edits of any other raw converter/editor. So, you have to work with a rendered version, and/or re-edit from scratch in a new raw converter/editor.
PS - it would be feasible to write a rough translator which approximated raw edits in one world into edits in another, but such does not exist yet for Aperture -> Lightroom, that I know of.
What you say is correct as advertised. However, after running a number of tests, it appears Lightroom copies over some (~1/3) of Aperture previews, but not all.