I love Carla. I had a second cousin named Charles, and he and his wife named their daughter Carla. I also knew a woman who gave birth in a car and named the baby Carla.
I dislike Carla. Carl sounds unpleasant in English and has a trying-for-macho image I find trying. And sticking an -a on the end to make it fem doesn't help. I even prefer Charlotte! And I named my daughter Caroline. But I'd never use Carla at all.