I chose the infiltrator class and have maxed out the cloaking ability. Overall the class and their cloak ability still seems disappointing when compared to some of the other class abilities.

So far I have been using cloak to get easy headshots with the sniper rife at medium range or to sneak up behind a small group of enemies and melee them. But both of these strategies mean that I can only take out ~1 enemy before becoming uncloaked.

What is the most effective strategy for cloaking?