Depending on what you like to do.
We normally take the bus/taxi (only JUTA) outside the port to the hip strip for $5 a person. Have lunch at Margaritaville and the walk to Doc's cave beach. I think it cost like $5 to get in and then you can rent chairs, unbrellas and even snorkel gear, the snorkeling isn't the best but it's ok if you go out at the end of the pier thingy. If you have your own I suggest bringing that. Although in July when we went the kids had such a blast on all the water toys at Margaritaville we never left there.
I personally like MOBay and have never felt unsafe there. Maybe it's cause I grew up in worse neighborhoods here in the states or as my Jamaican neighbor says they sense the crazy in me and let me be