Well these schools can differ a lot in what you might want exactly but as for locals in Dubai or any other emirate, the best secondary school to join would be @Institute of Applied Technology but for other nationality most would recommend @The International School of Choueifat
but there are many just as good schools in both secondary and primary learning like @Raffles International School, West Campus , @Al Mawakeb School and @Dubai International School. These are not the best but they've brought up good quality graduates which is all what parents need. Doesn't mean all the rest are bad schools.
Another school I recommend for British curriculum would be @GEMS Wellington Academy Silicon Oasis .