This hotel was the Arrabella Sheraton and is now the Sheraton. The whole place looks as though it has recently been refurbished and was extremely clean. Staff were very friendly and helpful. One point: although I asked for and booked a double room were were told that they don't really do a double room as such. (But we were moved to a room where two singles had been pushed together).
We were catching a flight the next morning and the airport is so close (literally a walk across the car park) that it is ideal for someone trying to get an early flight.
For those heading to Dusseldorf city -- taxis are pricey enough but catching a train into the city centre is very easy to do! Over all it was a lovely stay