I know it's a common complaint, but I -need- to put my 2 cents in....
They SUCK. They ruin the game. After spending hours building up a gravity well, 15 antistructure units can destroy everything in it within seconds. Long before s fleet from the next gravity well can get there, it's all gone. I fucking hate them. I truly hate them from the bottom of my gut. I hate them so much they make me feel ill everytime I decide to play against a TEC or Advent AI.
I mean OK, lets think about this logically, the Titans aren't even a tenth as strong as antistructure units.If those little weak ass Vasari bombers are supposed to fill the same role, don't you think that antistructure units are overpowered? Well, they are. They need about a 16th of their current damage output and half their current range. It's totally obscene.