K.M.
I actually lived in Puerto Rico for two years, but that was a long time ago. My husband and I went back for a vacation and loved it.
My biggest advice to you: get out of San Juan. Okay, spend a day or two there and go to the tourist sights- El Morro, Old San Juan, the Barcardi Rum Factory, etc., but then LEAVE.
Fajardo has a beautiful resort called the El Conquistador. Look at the website, it's amazing. That is where the hubs and I stayed when we went.
If you are taking the kids, arrange for a tour of the Rain Forrest. You will love it.
If you are familiar with VRBO, you may want to look at condos in Luquillo, (pronounced low-key-yo). The beach there is beautiful.
Finally, look into days trips to Culebra and Vieques.
Enjoy the food, sights and sounds (listen for the coqui frog- you will only hear it in Puerto Rico!) of this beautiful island. Have fun planning!