The app for Mac that is sold through the Apple store was not supported when the Mountain Lion OP upgraded, which meant that anyone who tagged using the app and upgraded to Mountain Lion lost all the tags (which is awful!).. The app does not embed the metadata, but the pro version does. That is a huge consideration in buying he new app, which is being sold directly through ACDSee. So, if I had it to do again I'd go with the pro version. It is new to Mac but I have not heard any complaints about the pro version. I am not positive you can convert the database from a PC to Mac, but I think so, as long as the metadata is embedded, which it is with the pro version. However, you probably would have to re-purchase for the Mac so if it were me, I'd wait until I had the Mac and only buy it once.
ITA with the suggestion to tag previews. It's easy to do right when you dl kits and is a super helpful tool.