People are nice in Brisbane
Sydney has cleaner water (just dont drink the drinking water

)
Brisbane has less traffic
Syndey is more expensive to live... particularly if you are doing a lot of driving
Brisbane has better wind
Syndey has better beaches
If you are prepared to drive 1.5hrs on a weekend then Brisbane has better beaches
Brisbane has warmer water
Sydney has better mountains and hiking
Syndey has better surf
I think brisbane that levels score at 5 vs 5...
You would kite more in Brisbane due to more wind, better directions and less gusty. Sydney tends to get more offshore gusty winds due to the headlands and the mountains to the south and west and the steep rocky headlands. The northerly winds bring in the bluebottles.
If you are just as happy to go out surfing then Sydney is the far better location for after and before work surfs (if you can handle crowds that is)
Both cities have too many jellyfish.