I love good raiding units - Raid Starships, Space Planes, etc are some of my favorite units. So not too long ago I thought I'd try out the unit that is, after all, named for raiding, and see how it compares.
To be honest, I was not impressed. Raiders are ~incredibly~ expensive, especially considering their massive unit cap. With a price like building a bomber and a frigate at the same time, it's hard for my economy to generally support them - much less cap them, which for just the Mark I variant costs something like 240,000 of each resource. And the worst part is they are extremely fragile, to the point that I generally lose a fifth or more of them on any given raid, which again forces me to spend large amounts of resources replacing them.
The point of a raiding party is basically to save you resources. By taking out a strategic target inexpensively (compared to sending a full fleet and getting bogged down in a real battle on that planet) raids allow you to save money for the more important things. Raiders, however, seem entirely counter to this idea. Between their high cost, huge cap, and relative frailty, Raiders tend to cost me more money than any other bonus ship I've yet played with.
So I guess my question is, what am I doing wrong? How do I turn Raiders into as effective a raiding unit as the devastating Space Planes?