Things should improve with familiarity, but moving to the Mac is not all peaches & cream.
The delete key does a backspace, instead. And it takes two keys (fn+delete) to do a real delete.
In Thunderbird, command+up-arrow doesn't jump to the top of the message list the way home does under windows. (Hmmm... fn+left-arrow seems to do that. How surprising!)
Accessing menu items from the keyboard is clumsy. It requires fn+control+f2 to select the menu, then the first letter of the menu item or walk over with the arrow key, then return to open the menu.