Joanne is OK, a bit dull, but OK.
Joanna is better.
Johanna fires my imagination. But
Joan is dearest to my heart for personal reasons.
Wait. I forgot about
Ioanna. Loads of character with
Ioanna.
I know, I know. You only asked about
Joanna. But my mind flits about quite a lot.
Joanna is a nice, elegant classic that gets overlooked. She's an underappreciated work horse that should get more attention.