The windows and walls seem to be fairly soundproof. If you open a window, you will certainly hear some noise, as the sea planes taking off from the harbour airport can be fairly noisy and frequent during the middle of the day (obviously, not at night). But, I didn't really hear it in my suite.

To me, I would say that booking Fairmont Gold is worth it at this hotel, even with breakfast included. The Empress has a fantastic lounge and private terrace. As for the difference in rooms, the entire hotel has been fully renovated recently, so no matter what room you book, it should be nicely updated. The Gold rooms are decorated a bit more, but if you have a look at photos online, you'll see they all look good. I'm not sure if there's much of a size difference. I think the positioning of the Gold harbour view rooms is nice, being right in the front of the main building. Harbour view non-Gold rooms would be set back a bit further from the road and harbour, but should still offer nice views.