I own all of the Sims 3 expansion packs & this has to rate as one of the best. It's great to be able to build & run your own holiday resorts again (remember the original Sims "Holiday" pack ?), and the new pre-made resorts are brilliant - they even have swim-up bars in the swimming pools. However this pack also has lots more features to explore.
You can now build a stilted home over the water or even build your own houseboat. Just look for a "port" site and select the "set houseboat" option. Once it's completed you can sail it & dock it at all the port locations around Isla Paradiso (the new tropical island world). Instead of the family car, why not buy a boat (power boats, sail boats even swan boats are available) - and sail out to the best beaches & dive locations. You can windsurf, or if you build up your snorkelling & swimming skills you'll be able to scuba dive under the sea (different dive locations are unlocked as you build up your skill). Watch out for the sharks !
There's a new life-form - mermaid. You can't make them in "create a family", but if you befriend a mermaid they can join your family as a playable character (baby mermaids are possible), or you can actually become a mermaid if you're able to get hold of some "Mermadic Kelp".
There's 4 new lifetime wishes, 7 new lifetime rewards, new traits, a new career (lifeguard), and of course new(water related) ways to die!
No instruction manual, and not a lot in the way of specific in-game help for this expansion. I've been playing the sims for years, but I found myself searching the Sims 3 community forum to work out how various new features work (like how to build the houseboats). Apart from this however, it's an excellent pack, lots of fun & I would definitely recommend it.
As always remember it's an expansion so you need the base game to play it - and check out the "Can You Run It" site, if you're not sure whether your computer has the spec to handle the game.