I'd buy it, but first I'd like to ask if After Effects CS6 is really compatible with my new Mac OSX Yosemite. If this were not so, I would like to know what I should do (before, during and after installation, if it's possible).
Thanks for your help.
Please check the bleow Adobe blog to check the compatibility of After Effects with Yosemite.
You can download a fully functioning thirty-day trial of CS6 (version 11 of AE) and see if it works for you. But you will have to update it to 11.0.4 to work on Yosemite.
You can also get a trial of the newer version CC (version 12) or CC 2014 (version 13).