Related: the basketball coach who always did a full-court press: http://www.newyorker.com/reporting/2009/05/11/090511fa_fact_...
In high-end college basketball, or the NBA, full-time full court press can become a recipe for easy fast break points. Inbounding teams can pass faster than defenders can run, and smart, disciplined players can memorize and run dozens of full-court plays.
At minimum you need a deep bench to consider it, because it is exhausting. So it's perfect for a kids team, where getting all the kids into the game is a virtue in itself.