I have done both, and if your idea of partying is bar hopping some great bars, do the pub crawl. My wife and I were on the bus on a slow day and had a blast. Would be a awesome with a good crowd. Pelican bar is chill and more of a relaxing place to trip out at. I want to go back there, but with a lively crowd.

Or do both on separate days. I did both my last trip and thoroughly enjoyed myself... Getting out of Negril for a day is a nice getaway. Different vibe for sure. And I would recommend doing it mid trip to break it up.