Sick. I would sharpen some areas of the nebula a little to give it some (more) depth. Also, the motion blur actually hurts my eyes and takes away from the piece. I would just do a simple blur and even burn some of those asteroids to soften some of them up by making them darker, thus creating (even more) depth. I would sharpen the spaceships a tad. I wish the nebula itself was bigger and more full in some places.
Execution needs work but I really do like this.. Colors are lovely. Clearly I'm obsessed with depth and sharpness.
You don't often see a beautiful nebula and sci-fi ships together like this...often a nebula on its own can be a bit common while ships on their own are often very dull - nice mix I do admit that I can easily tell at least 6 of those asteroids are duplicates of the biggest one But what amazing colours!
The colours and the nebula are as slick and beautiful as ever. But there is something that doesn't look completely right. Dunno if it's the motion blur of the asteroids that I really don't understand why it's there - or if it's the composition or what. Dunno.