Is attacking the queen side inferior to attacking the king side?

king or queen side attack is often dictated by opening play...for example in the Sicilian defense...blacks best attacking chances are generally on the Q-side ...this is due to the queen bishop half file, which is created when black takes whites queen pawn with his QB pawn...alternatively whites best chances, are a king side attack...if black can survive whites king side offensive and then can break through on the queen side ...you will see a victory with a queen side assault [:

I find it depends on pawn structures and the nature of the opening. Is it more Ruy Lopez/Spanish style or Queen's Pawn game? And of course your depending on what kind of player you are you would choose which side to expand to.

More often than not, there is no "Queenside attack" per se because it results more in positional advantage such as space advantage or acquisition of the c-file.

Just my two cents.