I was there a couple of weeks ago, It felt more like Vegas than Mexico in some parts. It is not your typical mexican town.

I would agree that unless your are going to hang out by the hotel (the JW has a couple of restaurants within walking distance) you may want to rent a car. Two things about renting a car a) they are going to try and soak you for insurance (38/day) so organize with your insurance company for coverage before you go, and b) watch out for these people that pretend to be part of the rental agency at the counter that try and talk to you about your visit, they are trying to get you to go to timeshare presentations.

The beach was nice but the surf this time of year made it difficult to get in.

There are plenty of amusement type parks that there are tours to that you can take your kids to but they will be in the 80-100/person range.