I like it over all. I'd need to see more view angles to give a firm opinion, but based on what's here:
I'd have to agree about the rock textures, but after looking at it a few times it starts to look pretty good. I'm not a real fan of the particular hull plating texture you've chosen, and the light tile looks a little stretched on at least one place. For vanilla FS2 though, this easily matches the Volition origionals for quality, and surpasses them in some cases. I think this one looks better than the Boadicea in most respects.
The really iffy part is the thruster exhaust ports. The nozzle part is fine, but the filler part looks out of place.
Shapewise, what are the two chimney looking doodads on top of the tower?
You certainly have a good start here - keep up the good work!