I would do Posts... but some studies show that pages rank better. I woudl do both and see which ones rank faster and higher. Then stick wtih those.

Hi Monica. Remember that you can always change a post to a page or a page to a post. You can read more about it here: Turn a post into a page. .
The comments are very helpful.
Blessings
Hennie

You could certainly use pages to centralize links within a category. For your example of macro photography, you could write a page about the topic as a whole, with a short introduction to each provider, then link to your post about that provider. You could also make each of those posts a menu item under the heading of "macro courses" (or something along those lines). If you look at the image, each of those are links to posts on my site, but they can also be reached through the main menu. Hope this helps.