Even basic products like non brand name food products taste cheaper/shitter so I have no confidence in generics from India. I know for a fact that Kelloggs cornflakes taste nicer than the shitty cheap supermarket brands. Ditto with Heinz baked beans.
From a friend who has experienced two different generic codeine tablets they say one is weaker than the other despite the same mg dosage. I think they said it could be related to what binders there is. Similarly vitamin supplements are not all absorbed equally etc.
As a steroid user I have also taken sustanon 250 made in Pakistan and the British version and the Pakistani version definitely irritaes more as well as feeling underdosed - this despite the fact the drug is made by the same company Organon in both countries. I imagine that for whatever reason standards aren't as high in the 3rd world. Thats with brand name manufacturers. I am sure for generics it is even worse.
Bottom Line - At the end of the day why risk taking an inferior product when the branded stuff isn't that much more in the first place? Always stick to American, or EU stuff in my book and you won't be disappointed.
In the same way the counterfeit goods coming out of the far east wouldn't pass muster in a designer boutique the same applies to the drugs coming out of these third world countries.