You're telling me that, done in the same scheme, a Yamato custom looks better than a Hasegawa. That's ridiculous, to the point that I want to ridicule you.
Let's take the Blue Roses custom theme, for example. This theme is the most popular, I believe. When comparing photographs of the two, it is obvious that the Hasegawa blows the Yamato out of the water in terms of detail and level of realism.
While I'll admit the Yamatos have advanced toys in terms of detail and construction since the days of the chunky monkey, the Hasegawas have elevated models to new heights as well.
Purely in terms of aesthetics, the Hasegawas win, hands down.