That looks fantastic. My only critique [well two actually]
1- The Deflector on the Ent-A was blue, not amber. The amber deflector was only featured on the refit Ent from Star Trek: The Motion Picture.
2- This is one I have seen just about EVERYONE do, the blue markings on the engineering hull and nacelle struts is too blue. If you check the pics on www.ex-astris-scientia.com, you'll see that it is much more toned down. And on screen, it looks grey, not blue.
Dont get me wrong though, I love it. But being a Trekkie and having worked on part of the franchise, I'm a bolt counter when it comes to the Big E. Here are a couple pics of what I mean. First one is from one of the movies, second is of a close-up filming model that was part of the Christy's auction. So its 100% accurate.
Also, here is a link to pictures of the original filming model. During filming, after, and upon its retirement.
http://www.cloudster.com/Sets&Vehicles/STMPEnterprise/STMPEnterpriseTop.htm