People do prefer SUVs because of their more durable suspensions (needed to keep the car going year after year in light of PR's terribly potholed roads). That said, the drive doesn't need to be four wheel, really. Never hurts but it isn't really needed in PR.
Jeep clubs are very popular. You'll see them travelling around in caravans on the weekends. Unsure how much off-roading is available, though, as basically every inch of land is owned one way or another. Perhaps another forum member could enlighten us. I'd like to know what's available too if I ever visit the island again (I'm sick and tired of the crazy crime rate - too old for that now versus when I was young and in love with the place, and all of LatAm, regardless).
For Switzerland, I have a four wheel SUV and a four wheel sedan due to the snow. I've only been able to off-road twice in the SUV: Once in northern Italy and once in the Tyrol (Austria). Wish I could do more!