What are you people talking about? There is the Colossus MkII which has Safety Overides and built in Hammer Barrage and the Colossus MkIII which has 2 fighter bays. The MkII does not have any fighter bays and the MkIII does not have 3 fighter bays. There aren't any other variants.
Colossus MK II is only good for doing a somewhat prolonged burst damage with its built in Hammer Barrage which can catch out some ships. Once the ammo runs out in about 17 seconds, the MKII is practically useless. The Pathers equip them with so much weaponry that they can't possible fire them all. Their PD don't cover the front or rear, only the sides, though a human player can try to cover the front if they really want to. There aren't any range 450 small mounts either. I had some success with frontal Railgun, Light Mortar and Vulcan Cannons, thought it's doubtful you would want to use precious railguns on such a ship. Trying machine guns and light mortar practically makes the ship like one big bomb. In practice, you will never really want to buy this ship for its cost, or have the opportunity to recover it.
Colossus MK III is probably the cheapest fighterbay per DP, though if you are equiping it with fighters, since the drover can give extra fighters, it's not as good as it seems. It actually has a reasonably good amount of OP for it's DP so you can give it two bombers if you want to. Since it has similar stats to the MKII, in theory you can fight with it, but it's best to regard it as a massive Condor with no ability to defend its own engine. I think the Condor needs some attention to make it a ship people would want to use.
I had reasonable good success with Atlas MK II, even killing Capitals when supported. For its DP it can creat a nice anti frigate zone around itself. I did a recover only, bounty only run and recoving Atlas MKII was the only practical way to get ships good enough to face Atlas MKII themselves. Like the Colosuss MKII, it does prolonged burst damage, but can keep doing so without running out. I think I gave them Expanded Missile racks since much of their firepower is in their large missile mounts and only filled for the small mounts, the 2 frontmost and 2 rearmost mounts and left the mediums empty. The only problem with Atlas MKII compared with the Dominator is that it is bad logistically.