Which pain medications work better: mepergan, percocet, vicodin?

Which is best. The one that works. There is no such thing as a best drug, the one that takes care of your pain and has the least side effects (for you) is the best.
Depends. Merergan is a combination of Demerol short-acting, poorly absorbed opioid and phenergan, an weak antihistamine with anti-nausea properties. I do not recommend any long term Demerol use because of toxic metabolite accumulation. Percocet and vicodin are both opioids in combination with tylenol (acetaminophen) which can both be used for mild to moderate pain it the tylenol (acetaminophen) dose is kept low. Discuss with your doctor.