Then I will do the bombers, based on just using the FS2 ones and making them flyable. Most of this is from playing with the stock shivan bombers in my own campaign.
Sub-Zero
Nahema - Its fast. Its well shielded. It actually has an afterburner. Its secondary banks aren't too large though, but its primary weapons placement is decent. Its like a Herc 2, only faster. Its has a distinction of being slower with all power shafted to engines, which is amusing. Notably, the only decent (stock) Shivan Bomber to fly.
Cool
Nothing
Uncool
Nephilim - Its slow, and having no afterburner makes flying it rather boring (or exciting when you're getting shot at). It maneuvers decently though. Its got a good number of primary points in a single bank, and, as noted, they are decently close together so you could probably get used to dogfighting with it, but its really not worth the effort.
Taurvi - This sits on the borderline between Uncool and Seriously Uncool. Its only redeeming quality, really, is its centerline gunmount, which makes bomb interception easy...or would have, if it could actually move. No afterburner. Well, its also flat, so I guess that counts for something. its not a big fat target like the Seraphim. If you give it an afterburner, it actually becomes a decent bomber.
Seriously Uncool
Seraphim - While this looks good on paper with 11 primary points and four missile banks, it sucks. It has a gaping hole in its forward shield quadrant making it largely useless, and it just so happens that that's the shield quadrant that gets hit the most during a bombing run. Its monstrous size makes it impossible to even dodge blob fire. The primary points are so spread out, you'd be lucky if you could get all of them to hit a cruiser. The only one that you can remotely dogfight with is the triple-point mounted below. At least that has a centerline point that aids in aiming. Oh, did I mention it has no afterburner? Not that having one would do it much good.