I think this depends where you live, having worked a summer as a trolley runner for blister pack production, we produced thousands of blisters, and at the end of the line half got pharmacy own brand foils and the other half got name brand foils.

Same pills, same packs, same factory same standards and testing, just different ink on the foils. But the pharmacy brands would have shorter contracts so they would only be identical to this name brand for 6 months, then try might get a contract with another factory and be identical to another name brand there.

I know with some drugs (Warfarin is the only one that's instantly coming to mind) it is important to pick a brand and stick with it because the slightest change can effect the therapeutic value.

For myself, I have allergies so sometimes a certain brand or manufacturing company will use a filler, binder or dye I can't have. And frustratingly there are no ingredients lists on pills for fillers and dyes.