Superlative! May I suggest that you consider some variations to the design of the nacelles, and the aft section? I think much of the beauty of this ship has much to do with the more "aerodynamic" shape as opposed to the Defiant, as well as the lighter shade of the exterior textures. She looks fast and maneuverable.
Just please don't emasculate this ship, DJ. 8) The Defiant was a man o'war in every respect, and the Federation has more than enough science and exploration types already.
"I wish to have no connection with any ship that does not sail fast, for I intend to go into harm's way." - John Paul Jones, USN