I stayed in Conrad Centennial Singapore last month. It was ok. I wasn't blown away by any means - though I guess maybe because I didn't get to stay in the Presidential suite...

I stayed at Dubai Doubletree across from the Mall of the Emirates (the one with Ski Dubai). Again no Presidential suite but I felt I got a lot better service here than at Conrad Singapore.

But I'm a low-maintenance person ... your mileage may vary depending on your expectations.