Here is my recent experience:
Yesterday I booked a four night stay at Andaz Maui which includes:
Daily full breakfast for 2, 100 USD spa treatment credit per room per stay, Upgrade, subject to availability, Early check-in and Late check-out, subject to availability. The rate is listed as "Ensemble Travel" and is the same price as the "Standard" rate on the Hyatt website (which does not include the benefits). I was told the benefits cannot be stacked with discounted rates such as AAA or member rates.
When speaking with the Concierge representative, I mentioned the "Luxury Hotel & Resort Collection" which can be found on the Citi Concierge website, and includes pretty much the same benefits as MasterCard. I'm not sure if the benefits are related to being a Citi/Prestige or MasterCard cardholder, but in the end it didn't matter because I am both (but probably Citi/Prestige as mentioned in an earlier post). In the Terms of Use on the Luxury Hotel & Resort Collection page, "Ensemble TravelŪ Group" is referenced, hence the rate code.
Additionally, I am "eligible to receive a complimentary fourth night as an exclusive Prestige benefit," verified by both Concierge representative and confirmation email.
Prior to booking, I emailed Concierge asking for a list of hotels on Maui that are part of the Luxury Hotel & Resort Collection. There are many other included properties not listed on the Concierge website, for example the Hyatt Regency (which I also booked for four nights with fourth night free, but with a AAA rate instead).
tl;dr
Search the Concierge website to see if the property you want to stay at is listed under the Luxury Hotel & Resort Collection. If not, email Concierge and ask them for a list of included hotels in the area you are traveling, which may include your desired hotel. Call Concierge to book and reference the Case Id from prior email communication or Luxury Hotel & Resort Collection or Ensemble Travel Group, and hope the representative can find the rate. Verify the rate, included benefits, and fourth night free.