We thought the JW was a very good property: for only 20k difference, I think I'd want my room there over the Casa Magna. Casa Magna is also good but has more of a "normal Marriott" feel. Sure, you can use all of the facilities of both buildings no matter where your room is, and maybe this is just a style/preference thing. We liked the JW.

As a Plat, I redeemed two Travel Packages there simultaneously. Suites appeared to be sold out so I didn't want to gamble with one award. Since I booked two rooms and requested adjoining rooms, I think that pretty much killed my upgrade chances. Still: we did receive a high floor, they got the request right without issues, and all of the rooms have an excellent ocean view.

We elected not to purchase the Club 91. That would have been over a grand with taxes by itself just to do 1 room/2 adults. Since we knew we were going to have at least 3 days totally offsite, it seemed like a waste. Plus, the service didn't sound all that different from the Royal Beach Club service found at some Mexican Starwoods, and that's $40 per room per day. (I think RBC only has three food presentations per day, but it's a full open bar and enough of a hot evening spread to serve as a light dinner.)

On a weekend getaway without plans to leave the hotel, I think Club 91 would have more value. The value of the airport transfer would carry more weight.