Originally Posted by RadioGirl

I have, twice (April and June 2013). It was clean, quiet and functional; looked pretty much like any high-end chain hotel, but quite satisfactory for a shower and a night's sleep. It's a bit more than I usually pay for just a hotel room, but in this case the convenience is worth it.

The best feature, perhaps, was being met at the airbridge by a hotel employee who facilitates the security checkpoint (barged to the front of the queue ), helps with carry-on bags, navigates to the hotel, and takes care of the check-in process. Make sure you indicate your arriving flight details when you make the booking to get this service!

In the morning I had breakfast in the J lounge in the A380 terminal. (If you're there for 18 hours you could come and go between the hotel and the lounge as desired...)

I did not use the hotel restaurant/room-service or other facilities (there's a pool or gym or something?) but happy to answer specific questions about the hotel itself.