I read you had trouble with quality while saving, which file type are you saving it as? Cause that might be why.
Anyway, I really like this man, love the stars and I like the way you're using color variation, I cant really find much to critique on, but if I had to find something, it'd be the "sharp" spikey looking parts of the nebulae, maybe try using some more fluffy flames to layer over those sharp pointy parts, like some very small ones, I believe that will bring out the nebulae a bit more, but still, this looks really good, just keep at it man, you're doin really well!