I have been using genhydro cocotek. I have used sun leaves, and some other brands. They are all pretty much the same to me.
I just toss a 5 k brick in a 18 gallon container, add 7-10 gallons of water, then wait. Nothing to break up.
I buy bricks because the take up less space. 10 don't take up much room. And they are cheap. $11 for a 5k brick.