In my experience the drones are best against ships without PD, the drones have pretty good range and seem to me to basically just let you use laser tech for long range if you haven't been keeping up with your missile tech. They also have the advantage of being able to target a specific part of a ship. Missiles can't really do that. So with drones you can take out that huge antimatter projector from afar, while with missiles you kinda have to just fire off a macross and hope for the best. Drones also can't really overkill. If you fire off 30 missiles and the ship blows up at missile # 3 the rest of those missiles are wasted. Drones just retarget and keep shooting.
My advanced drones with dual phazors seemed to out damage my missileboats fairly well. I imagine they can do more damage per second than missiles can at similar tech. But like missiles they lose out on most of their advantage fighting close up.
In my experience, if a cruiser size up doesnt have PD, its just a target in space. The AI knows this, and thats why almost all of their ships have it, rendering drones useless till you research fusion drives and swarm them on cruisers or higher.
However, I have never played against a human player, they are probably more effective.
Personally, im more of a mass driver dude, AP rounds wreck havoc. I destroy more Hiver cruisers with my wimpy hulled Morrigi cruisers than I lose cruisers. Of course, late game I tech up energy, since its way more powerful with a lot of research.
And finally, thanks for the population advice. I will have to check that out later.