I went for a test drive yesterday in an SLT-2 with the HUD. The sun came out and so I put my shades on. To my surprise the HUD disappeared. I thought that the HUD was broken initially but when I took my glasses off it came back. I can only assume that since my sunglasses are polarized that this has a conflict with being able to see the reflection off of the windshield. It looks like I will have to get a new (less expensive) pair when I drive the Acadia. Anyone else experience this?