Thanks for the info about the issues.
I used the beta version, and it was slow due to all the debugging software (according to some). I upgraded to LR4 and had some difficulty upgrading from LR 3, I tried a second time after restoring from backups and it was fine.
I just imported a image to ps5, and did get a warning message about acr 7, but clicked import anyway and there was no problem.
The speed issue also seems to have gone away, but there might be some function I haven't tried that is slow.
I like the new automatic CA removal tool, its much more accurate than the CA correction stored lens by lens. I had no trouble finding it, but then, I viewed all the short video's discussing new features and how to use them.
I've done a few hundred edits now, it seems pretty solid, no crashes and only minor issues that will be fixed.
I might save the new edits that were done in LR4 in a separate catalog, and re-install the LR3 catalog after the fix is out.