Scouts rip up colony ships.  1v1 the colony ship will win, but cost-wise there are many more scouts to a colony ship.
 
After doing a conversion for metal and crystal, a TEC colony ship costs 1125 credits, while a TEC scout costs a mere 200 credits.  In other words, cost-wise you can afford about 5 scouts to every one colony frigate.  Even after their damage nerf in 1.19, scouts are still pretty formidable when pointed against non-combat units like the colony frigate or siege frigate.
 
Also, Sin-related stuff belongs in the Sins forums, not off-topic 