@rolf great work! Moved to this Github gist. People could suggest changes there.
Now getting "Error: no such column: rating" (Clementine 1.4 rc1, Strawberry 0.9.3).

BTW, just to make it easier for others, default locations are

./clementine2strawberry.sh ~/.config/Clementine/clementine.db ~/.local/share/strawberry/strawberry/strawberry.db