Causes SEVERE slowdowns and increases loading times on nearly all webpages. Does not perform well at all. Would not recommend to anyone. The moment I uninstalled the extension, Firefox was immediately faster and smoother. I'll go back to using other extensions. Avoid Ghostery.
EDIT:
I reached to Ghostery support. I'll update if they reply with a solution. For now I am still firmly under the impression that their add-no does not provide a faster experience. Yes, it blocks trackers and ads, but my experience was very slow and unusable.