My first replacement iPhone 3GS is a week 24 with a slightly yellow display (bottom third more yellow), very loose silent switch and loose volume button. I just received a second replacement via mail due to the yellow on the bottom third, which I find distracting. It is a week 27 with very solid build quality and no loose buttons. However, the display is much more yellow than the week 24 iPhone. It is also more yellow towards the bottom. Which would you keep? Less yellow and loose buttons OR more yellow and better build?