I currently have an iMac 64bit, and a MacBook Pro 32bit machines. I'd like to stay up to date with Lightroom 4, however, I can't afford to spend another $2500 on a new laptop. So, the question is:
How can I work between LR 3 on my travel Mac, and LR 4 on my home Mac. Is there a way to open LR 4 catalogs in LR 3?
You could write data to xmp - it wouldn't contain everything that would be in the catalog, but the bulk of it would be there. LR3 wouldn't understand the new Develop sliders, but LR4 would be ok with the old sliders. It depends on what you need to do with the photos when you're traveling.
Not being able to use LR4 catlogs in LR3, will prevent me from continuing to work on images while on the road if I started them at the studio. I use the LR Slideshow for presentations to clients etc.
Guess it might be time to take a look at Apeture. I have been a Lightroom user from its beginnings. Hate to make a change, but I'm left feeling abandoned by Adobe.