Alright, tell me everything that’s wrong…
Cool, I found the Nebula a bit overpowering and the contrast made it difficult to see the details of the feature ship. Nice though, a bit sharpish, antiailised at all?
Awesome!
Three things stand out for me - after a few seconds of relish and wonder…
The ship on the bottom seems to lack detail - it’s very flat.
The ships are out of metal, so maybe make parts - not all - of the ships specular/reflective.
The engines on the main ship have a really cool glow, but the other ships seem to have none by comparison. Also, you could try playing with adding some trails/other particles.
Keep it up! By the way, I love your avatar! 
On the back of the main ship, it looks like part of the ship is sticking out through the glow, and that sort of ruins the effect. Other than that, it looks really good!
The modelling is fantastic, the lighting makes it look like a videogame’s, though. Too flat and one-dimensional. Here’s this. Try a large orangey area light or some such for the back light to make soft shadows from the nebula. There should be another fill-in light, sort of faint, light grey-blueish, maybe, from the side or the front, just to hint at ambient lighting from stars and other nebulae.
On other thing is the textures. They could probably use some bump maps.
And anti-aliasing, yes.