Hey guys this is my first time trying blender, hope you dig it 
Excellent model love the little details
I think you have too much reflection on it. Makes it harder to read the shapes. Most tanks/guns/war items aren’t that reflective.
I agree with adam450. You got a great model here and it can look a lot better with a few tweaks. (if you have the time and patience that is)
The model looks amazing. One thing I would recommend doing is making it blend better with the background images. You can use the compositor change the colors and make it look more like its in the same lighting as the background image.