Better than Outlook so far Rated 5 out of 5 stars
Still just learning it but I am not missing Outlook so far.
1. Copy and Paste events?
2. Help to research above seems lacking
3. Custom Multiple date events where you can just click random days would be good.
4. Can't search on Calendar in Add Ons in Thunderbird section and get Lightning.
This should receive more press as I held off on TBird because Calendar seemed not ready for prime time. So far, I would say it is or at least close.......