Good point. My personal preference would be for substance, but that's certainly a preference for visceral reaction over technical precision. This probably has much in common with the Truffaut/Godard debate as well. I would pick Truffaut because of his narrative, but I will concede that Godard is the superior film maker of the two.
Take the case of Alain Resnais's "Hiroshima mon Amour" and "Last Year at Marienbad", which are both structurally elliptical and thematically similar in the exploration of time and haunted memory. I tend to watch "Hiroshima mon Amour" more often because of the engaging story. Although "Last Year at Marienbad" is more visually stunning, it seems fragmented and serves more as an adept technical exercise than a treatise of human existence.