Which do you like better Island Paradise or Island living ?

Isla Paradiso. By a long shot. I understand that the world itself was buggy for many people, but I play in custom worlds usually so that's a non-issue to me. I do play in IP, but I do have a lot of fixes in it, so the state of the world to me isn't a dealbreaker, even while playing it. IP had so much more everything -- items, gameplay, and integration with the rest of the game. There were the active careers of lifeguard and diver (though that was more getting odd jobs) plus the sandbox career of running a resort. Plus being able to own more than one property, though you could only live on one which was a shame. And you could do everything in any world. It took a bit, but people eventually even figured out how to put dive spots in all worlds.

Island Living is just, well, lacking in content. Since I personally had no problem playing in IP and since many custom worlds integrate IP stuff into it, to me, the more content the better. I think things like tanning, building sandcastles and such came with Sims 3 Seasons, so I'm not sure how to count that in the "which has more" category.

I'm still trying to figure out why there are two types of rental houses you can assign to lots in Sulani. Since there are two, and the wording is slightly different, I wonder if they were trying to add in the ability to buy vacation homes or weekend homes or something and ran out of time and/or resources.