Full open access journals (gold open access) can be just as good as 'standard' journals - the difference is in the financial model (author always pays, as opposed to reader pays). The obvious benefit is that the publication will be immediately accessible to everyone who wishes to read it. And, of course, you as the author retain copyright with open access publishing.
The difference between gold (full open access) and hybrid journals is that with the gold model, open access is the only publishing option. Hybrid journals let you choose between open access (you pay) and non-open access (reader pays).
With hybrid journals this can sometimes lead to a sort of double-payment situation, if one is part of an institution that already subscribes to the journal. The institution pays subscription fees, and author payment for open access comes on top of that. Where I work, we usually advice researchers to go with the non-open access option in these journals, and instead make the accepted manuscript version available by other means (e.g. uploading to an institutional archive or a subject relevant repository).
I recommend using the Directory of Open Access Journals (doaj.org) as a guideline for finding quality gold open access journals.