Everyone talks about the bravery bomb as a method for removing models via battleshock, and therefore give it no value versus armies with immunity. I went with a different use for the bravery bomb and have found it to be quite usefull. Bravery debuffs can be be a great way to inflict mortal wounds in an aoe, which makes it very hard for your opponent to recover as you create pressure on multiple units at once. With multiple units at -4 bravery the mortis engines/olynder are a great source of consistent damage, and the banshee can focus on heroes/special units.
This list may not be ultra competitive in the tournament scene but I have faced serveral armies that have a tough time with it. The zombies/chainwrasps are hard the chew through and the skeletons can punch back pretty hard with van hels. Hide your heavy hitters just behind your front line and deal consistent aoe pressure. I usually pop both of the mortis engine once per game abilities on round 2-3 when the most enemies are in range, and the healing helps to counter act any shooting at your engines.
In more casual games its not at all hard to table your opponents.