An enjoyable puzzle, but, as others have noted, the puzzle yields very quickly once the theme emerges - in my case after seven across clues solved and enough downs to reveal what had to be the thematic entry in row 2.
Although it wasn't necessary to solve the thematic clues (a defect in my view) I did after completing the grid. They are actually very good and paired very nicely. I think I would have struggled to cold-solve some. Even knowing the answers it took me a while to work out which clue led to which answer.
The thematic symmetry of the grid is a very neat accomplishment.