I used CC back in the day, but it became a pain to manage, as images would have their copyright changed by the owner (nothing wrong with that, but a PITA to manage and replace), or images would disappear altogether (leaving a nice "image not available" message on your post).

I use a mix of Unsplash and Pixabay (moreso the latter), and am more than happy with both quality of work and quantity of choice on display.