Keep in mind, I only have these two pics to evaluate from. And sometimes I have problems expressing what I see, into words......
The silver bird just doesn't look as balanced or pleasing to the eye. He looks too leggy, I guess. Wyandottes are supposed to be "gravy bowl shaped", with deep bodies. His front line, the chest seems shallow, for lack of a better term. There's not much breast there, it ties in high to the body. Overall he looks more upright built, not a desired feature.
The gold bird seems to have more of the classic rounded shape, although he's still a hatchery bird. His legs and back seem more in proportion to the rest of his body, making him more balanced overall.
Again, some may be the angle of the pics. You can see the birds in person and will be able to better judge them. Wider bodies are usually a good thing, so keep that in mind. How wide bodied are your hens? If they're decent themselves, you don't necessarily need to compensate for that in the next generation.
You might ask Bee if she can articulate better why the gold bird is nicer, conformation wise. She may be able to pin point something I couldn't. I just know I looked at both of them and my brain said the gold bird was a bit better quality than the silver.