Meant to do this comparison since a long time. Here it is: Top Side (except Mastodon as it didn't fit)
Stork is easily the best by a large margin. It has very thin middle part and nice ablative armor plating (cargo pods). The result is you need to subtarget its front part which has the size of a ~3k transport. Every single one of the others is easy to hit.
I used the Rheinland Trains for a long time in .86 for supplying and independent trading. It actually flew like a dream. Easy to hit lanes, rarely got stuck regardless of its size. I still got rid of them though as it seems the camera has been confinangled (technical term). The view puts you almost 1/3 the way up the ship, and when you tilt down, it's rear literally fills the entire screen. I'm not sure if they messed with the camera or the size, but it's neigh unbearable to fly now. Shame to see such a nice transport relegated to this.
Pretty sure I told Aeternus about it on skype at least once as well, and he said it would have to be resized.
Only good thing: there's a good chance of not getting CD'd by a TCD from behind.
Besides that, I owned a Colossus once. Did a low level "kill one NPC" mission in Tau-23 with it in .85 with the old NPCs, way before .86. Took me about half an hour at least.
Are you implying the turrets are useless? Because they aren't, I can attest to that. I've kept the shields down on a gunboat, allowing my Arrastra miner to chase it away with SNACs, or deterred a Spatial pirate entirely.
They're not going to kill anyone outright but they are far from useless.