I bought a Lumia 900 last week from Amazon and overall everything was ok except the purple background (under low/auto brightness) and vibrate rattle. It came with the green dot on the box but with the old firmware. I updated to the lastest, nothing changed. I was not happy about these two issues and I called Amazon for a replacement, I got it today. It came with the lastest firmware loaded and there is no purple issue under low/auto brightness or vibrate issue and the new one has much better battery life too. I'm so happy that I got one without these issues. I tested little bit about the capacitive button issues, so far nothing found.
Thanks everybody !!
Thanks everybody !!