My Emperors Children army is officially feared in my gaming community. I've played several games vs World Eaters, Thousand Sons, Nids, Astra Militarum, and Tau now and the consensus is that people don't like playing against my EC. Mostly I've run the Kakophani formation with the Obliterator detachment which has proven effective time and time again. Most recently I've tested out some different builds using the Warband detachment with a Spawn auxiliary and a Daemon Prince as a comand choice. I've also given Lucius a shot as a way to get an extra doom siren into a foot squad of Noise Marines. Verdicts are as follows:
Lucius: In the past I've panned him as a sub par choice but after using him in the Kakophani as its Lord I appreciate him much more. He will never stand toe to toe with great beat sticks, but as a way to get a second doom siren in a squad and get a challenge bot he works great. The big plus side for Lucius is he doesn't have a preset warlord trait which means he can generate a good one off of our great Leadership table with a reroll if you get a duffer. He also covers the AP 3 high initiative side of the challenge spectrum which lets you put a power fist on the sergeant for the heavy hitting. In a large unit of Noise Marines mounted in a rhino with an Icon and extra CCWs, Lucius represents a huge roadblock to opponents, hard to kill with shooting but deadly dangerous to try and shift in CC.
Warband: Mixed feelings. I appreciate it as a way to bring a greater variety of units such as a squad of raptors or terminators to our army along with obsec, but in my game against the Tau I kept finding myself missing my Sirens and Blastmasters. The utility of having CSM with melta and plasma guns never really paid off in my favor. The Raptors proved a very keen addition to my force, but I can add those to a Kakophani via the raptor formation. Obsec never really paid off either, I have better luck clearing objectives with turbo powered sirens rather than trying to use obsec to capture points from units I can't shift with regular weaponry.
Spawn: I found my tax spawn terribly useful in my game for capturing points and eating overwatch. I need to think of a way to do a clean conversion that will fit in my army (my EC don't have spiky bits or mutation, they are clean pretty boys of the 30th Millennium variety).
Daemon Prince: My god he carried me to victory in a Tau game. Between, Combat Drugs, Elixir and a random Boon of Mutation I got +1 WS, BS, Init, A, & T. Also rolled the 4+ FnP and the nova scream on the psychic tables. In one game my Prince killed: 2 squads of Pathfinders, 2 squads of Breachers, a Crisis Suit Commander & drone, a Ghost Keel and two drones, and a Stormsurge battle suit. The only things he didn't kill himself was a Riptide, 2 squads of Breachers, 1 squad of Pathfinders, and two three man Crisis Suit teams. The Prince really gave me the speed and hitting power I've been lacking in the past. I'm really considering a list built around the Kakophini and Raptor formations with Spawn and a Prince added in for my next matchup.