The Aperture Trial has gone remarkably well. Aperture 2.1.1 appears to be a stable product with only one drawback that I have found so far.
Lack of speed.
Yes, what the pundits say is true, Aperture doesn't react as fast as Lightroom, particularly on my aging PPC PowerBook, right at the lower end of computers for which Aperture will work. But sooner or later I will have to upgrade the computer, that is inevitable, so this point will eventually become irrelevant!
But for all that I simply prefer the Aperture workflow and also I find the output options are much more flexible.
So I have purchased Aperture and am now moving over from Lightroom without even testing their latest offering (2.0).
I did make one mistake while purchasing Aperture; I tried it out on a fast new iMac. Wow!