My (albeit limited) experience from test riding was that cheaper frames tended to use old straightforward designs that were poor at handling road vibration. I'm kinda of sensitive to it. You could also consider that the better aluminum bikes come with a carbon fiber fork that can also vary in quality. The more recent and more expensive aluminum frames handled road buzz far far better. I test road a Giant frame recently and was kinda shocked how decently it rode over potholes etc on the road.

I think you get a little bit better quality in the materials and build, but where you really benefit is better design.