I depend a lot on aliases to files and folders. Just after upgrading, most of those I've checked, aliases that worked before the upgrade, fail now. I get the usual error message, "...the original item can't be found,..." which offers the option to Delete or Fix that alias. It seems I can fix the broken aliases, one by one, but it would be good to a) understand why this happened and b) to find a systematic fix, if any.
In at least one case, I noticed an 2 year-old alias to a folder I renamed about 6 months ago seemed to indicate, in its "get info" the previous name of the original folder. I use this alias routinely, and I know that prior to the update it took me to the folder per its new name.
So: it is AS IF MacOS 10.8 uses a revised alias database (?) and there was a problem transferring the data from the 10.7 database.