All three OTC pain-killers mentioned are roughly equal as pain-killers in my experience. They all have other and different secondary uses. Ibuprofin will work as a muscle relaxant which the other two won't. Aspirin will work as a blood thinner which is why many recommend it at first sign of a heart attack. If the heart attack is caused by an embolism then aspirin will potentially thin the blood enough to allow it past the embolism and save the threatened cardiac muscle. Aspirin will also lower Blood pressure. Acetominophin is an analgesic pure and simple. I find that all of these are synergistic with caffiene for minor head aches. (That may be due to my personal caffiene addiction ;^O).