I've recently switched to Lightroom (LR) from Aperture since LR came with my Leica M-E purchase. I have yet to merge my older Aperture library to my new LR workflow. So I'm sure I will see some major changes to how my older files are rendered.
BTW, this past week I purchased George Jardine's Lightroom Library Workflow and Develop Module videos. I've completed the Library workflow and can say it was an eye opener and now have confidence once I've finished moving my older files over I will be able find any photo from the past.
I did a quick blog entry here:
http://blog.duanepandorf.com/2013/03/21 ... nt-series/