There is a good summary at https://www.openaccess.nl/en/what-is-open-access/pros-and-cons.

See also these previous RG discussions:

https://www.researchgate.net/post/What-is-a-open-access-journal-How-can-we-recognize-it-and-what-are-the-benefits-to-publish-a-journal-in-it

https://www.researchgate.net/post/Should_all_scientific_research_be_made_open_access

https://www.researchgate.net/post/Open_access_free_of_charge_should_we_change_the_roles_of_publishing

https://www.researchgate.net/post/Free_science_What_do_you_think_about_paying_to_read_a_scientific_article_even_though_you_know_that_its_authors_dont_get_paid_for_it

https://www.researchgate.net/post/Open_or_closed_access_journals_What_is_your_take

https://www.researchgate.net/post/Is-open-access-journal-is-better-to-publish

https://www.researchgate.net/post/Free_Articles_Downloads

I have also written a paper, viz. “Writing for Publication for Students and University Staff”, which briefly discusses this topic (among many others) and is directed at new authors. The paper is freely available on ResearchGate: https://www.researchgate.net/publication/342549330_Writing_for_Publication_for_Students_and_University_Staff.

One of the problems of open-access journals (and open-access papers in subscription-based journals) are the high APCs. This has been discussed here and in several other previous discussions:

https://www.researchgate.net/post/Why_does_Nature_Open_Access_charge_so_much_to_publish

https://www.researchgate.net/post/Publishing_open_access_for_1000

https://www.researchgate.net/post/Is_it_true_that_only_open_access_journals_charge_publication_fee_while_subscription_journals_do_not_charge

https://www.researchgate.net/post/Scientific_Journals_with_Open_Access_and_no_APC_free_charges_for_authors