Hotel Name: Grosvenor House, Dubai
Arrival Date: 22-04-2013
Departure Date: 05-05-2013
Number of Adults: 2
Number of Children: 0
Number of Rooms: 1
Room Type: Deluxe
Starwood Brand Web Site Room Rate: AED 21,420.00
Other Company room provider: clever-hotels.com
Same currency: No
Competing rate: GBP 3177.00
Actual confirmed rate: AED 16,070 (after 10%)
Response time: ~24h

Above rates include 20% tax and are total per stay. The competing rate had breakfast included and apparently SPG matched that one too.

I also found a useful website for finding cheaper rates: http://www.trivago.co.uk