I really like the overall impression/look of the image. The colors and the light go together very well. A lot of action is happening but I think it really has the right amount of elements and isn't overloaded. It's a hard task to display epic mass-battle scenes in space and I only can imagine the time it took you to complete the ships.
My only critique are the two ships on the left that are flying towards viewer. I'm not sure about their actual size. The bigger problem is the one above the large battlecruiser. Perspective seems a bit off and it maybe would help to move it in front of the BC. Or enlarge the length of the jet blast to give it more depth and to define a certain size for this ship-class.
Nevertheless: keep up the good work!