I agree with Rags; it's almost perfect, just a little more work on the tail end. The overall shape of it is just excellent!

It feels kind of rough and unfinished, especially around the tail fins and rear engine. The color scheme as well could use some help; having a dash of red on it is a good idea, but maybe try and organize it so the red is in a stripe around the ship instead of in patches, that will make it look a lot more coherent and interesting. It's a good idea and looks cool though, so keep up the good work!