I had the chance to play the JLSG Darkseid at 400 points in a 500 point game.

My force was:

400 Darkseid
3x33 Parademon Grunt

The reasoning behind the team was that I'd have a named keyword team (Apokalips) with four Probability Control chances (and characters to take them) if Darkseid missed any attacks. I only played 1 game against a GotG Fast Forces team, but I can give a sense of how the figure plays.

I lost map choice and went second, so on my first turn I had Darkseid carried up to where he could use "Omega Beams" against the one characters with Precision Strike. On turn two he successfully used the Omega Beams to cripple that threat.

The rest of the game became one in which the other team was trying to position to attack Darkseid and Darkseid continually spawning Parademons. My force's double power actions and the opposing teams made this a real struggle for both sides. Eventually I lost all 3 original Parademons and 14 of the 10-point BSTs! Darkseid ended up only being the target of 1 attack IIRC (part of a Pulse Wave that cleared out all five of the BSTs)

The Parademons did very little damage on their own, but they got a few hits in. I made sure to try to make sure I was going to lose ALL the Parademons at once so that I could spawn five more if necessary (and then attack with them, or Carry Darkseid away). I felt it was pretty thematic to have the Parademons dying left and right to slow down opponents so that Darkseid could eventually focus on particular trouble-makers to shut them down!

i've used my also, with great success. one thing i did that helped me alot. was i with move most of my parademons out to base my opponent's figures. they'd have waste actions KO'ing parademons if they wanted to make range attacks against my darkside. or roll breakaway rolls. i'd also get a plus 1's to my opening 12 attack from the parademons trait. thiat alone with the spawning trait gives darkside longevity & makes him very good late game.