Personally, I am tentatively on the side of the epistemologists, but it seems to me that details matter a great deal, and there are far too many details to discuss in a comment (indeed, a book is likely insufficient).
Even when insufficient, is there a book or other source that you could recommend?
Hmmm. Bas van Fraassen's The Scientific Image takes the side of the epistemologists on scientific questions. I take Kant to be an advocate for the epistemologists in his Critique of Pure Reason, though he makes some effort to be a compromiser. Rae Langton argues that the compromises in Kant are genuinely important, and so advocates a role for both epistemology and ontology, in her Kantian Humility. Heidegger seemed to want to make ontology primary, but I can't really recommend anything he wrote. It's difficult to know exactly what to recommend, becaus...
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.