Recently stayed at the St Regis Abu Dhabi 7 nights. Overall excellent stay and wonderful staff, pretty much as others have described in this thread.

The only weird thing was they totally ignored the reason we stayed there, which was to celebrate our engagement. I mentioned it to them beforehand (they never responded), and also upon check-in. So I thought they might leave a surprise in the room like you would get for a birthday or anniversary, but it didn't happen.