Since there is no calendar in Thunderbird that area is toasted. Contacts and emails should be transferable.
--> BEWARE THE SPAMMERS about OLM decoders and such. Just ignore them.
https://www.google.com/search?q=outlook+for+mac+alternatives&ie=utf-8&oe=utf-8 finds the prior discussions so I can see why you had Tbird troubles.
PS. Yes, I know about http://kb.mozillazine.org/Calendars_-_Thunderbird but I will not offer those since I've heard from folk that locked up or lost calendar information with those. My nod would be to try the Apple Mail and Calendar apps.
I am currently using Microsoft Outlook for Mac 2011 (Part of Microsoft Office for Mac 2011) for emails, contacts and calendar on a Mac. However, this version of Outloook/Mac sucks so tremendously that I have to move away from it. I want to use Thunderbird instead. Unfortunately there isn't available any method of doing the same.
Did anybody here do this move from Outlook/Mac to Thunderbird/Mac before and knows how to do this best?
Thanks and greetings.