The weapons in GalCiv beta 4 aren't well balanced.  We're moving towards the point when it's time to start thinking about how to balance the weapons and defenses.

In general, the idea is that defense technologies will be somewhat cheaper to research and be somewhat cheaper to put on your ship than weapons. But they'll both use up costly space.

So what's more important? SIZE or COST?  Cost is the pain that keeps on coming because the Maintainance cost on a military vessel is 3% its cost.  So that's $3 for every $100 it costs.  Make a ship that costs $1000 and you're looking at $30 in maint EVERY TURN. 

So the idea was that missiles, in general, pack more bang for the size they use but are immensely expensive.  Mass drivers are incredibly cheap but use up more space. And beam weapons are right in the middle.

So below is a chart in which we look at a series of different weapons in the game and how valuable (cost and space taken into account) they are for fighters and capital ships and how powerful they are (just space vs. weapon strength taken into account) for fighters and capital ships: