I haven't tried this in a game yet, just set up a few trials on my own against static units. But it seemed to be very effective against Marines and even crisis suits.
For 501 points you have:
Darkstrider, a fireblade, 10 breachers and two squads of 5 strikers with rifles in 2 devil fish with drones.
Run the fish up side by side into the unit you want to eliminate, engage in HtoH on that turn with enough space between them to be able to deploy the boys( and girls) next turn, standard 8th edition FOF.
Stager the deployment of troops with drones up front, then breachers within 5" of the target, the fireblade within 6" of the drones and Darkstrider beside him then both squads of strikers within 15" of the target. Both the HQs use marker lights, very probably getting the one hit needed for rerolling ones, even with moving, and unleash pulse fury! Maybe have one firewarrior lob a grenade in case there is anything left to assault with the drones.
Disadvantages; it's not cheap, and since the drones can't remount (even if they do survive) it's a one shot trick. There's also the risk that if the drones lose, the breachers will be consolidated into. But the remainder can fall back next turn and fire with Darkstrider there after surviving only one turn of close combat.
Advantages; it does give you a technical battalion in 2 drops and the target unit, if not a mob, should evaporate under 20 blaster shots, wounding on 2+( vs meq) and 50 pulse shots, all rerouting ones to hit. With the fish + drones as a screen, the firewarriors should be pretty safe and able to secure an objective.
Anything I'm missing?
Edit : found something I was missing