How effective is the slower ball bouncer when compared to the normal bouncer ?

Slower bouncers are used only in limited overs game invented by Pollock. It is bowled when batsman tries to attack the bowler. The batsman gets confused and mistimes it. Even if the batsman knows slower bouncer is gonna come, it is difficult to put away because no pace on the ball. On the other hand, normal bouncer can take a top edge and go for a four. Slower bouncers are bowled only when batsman seems to be attacking. But Normal ones are bowled when the bowler wants to attack. I hope it helps.

It's all about knowing your opposition and using the slower ball bouncer at the right time. If the batsman if looking to defend you use the fast bouncer, if he is looking to score then you mix it up with the slower bouncer.

you have to be more cleaver on this. if you bowl the bouncer too slow then batsman has enough time to pick it. i have seen Lasith Malinga bowls good slow ball bouncers.