The location is excellent, right on the waterfront in Darling Harbour and with a light rail stop almost outside the door to get you into Haymarket (and from there up into the CBD). Access to The Star and the Lyric Theatre is via a short walk (5–10 min) or the light rail. Walking is a little confusing at the moment due to construction next door, but you can go via the Novotel car park (cross over at the light rail stop, go up to level 4 of the car park, then walk out onto Murray St).
The soundproofing in the rooms seemed excellent. We didn't get too much noise from outside and didn't hear other rooms at all. The room was comfortable, modern, and clean.
The only issues we had were 1) the bathroom lighting is pretty poor for shaving and makeup (then again, most hotel bathroom lighting is), and 2) the new electronic (phone app) room keys didn't work at first. They eventually did work, using a completely different app (odd), though they were pretty slow to activate. Hopefully, they'll fix the teething issues soon because it is very convenient to be able to access the room using my phone and not a physical key.