I'll just begin by saying that this is the most beautiful mansion I've seen in Thief as of yet. It's gorgeous. Highlights are the chapel, ballroom, and the main hall. It clearly inspired DeWall's estate in The Long Shadow Falls (The Black Parade). Beautiful.

The gameplay is great fun, mostly because of the mansion itself. It's open (quite the contrast to Ominous Bequest's location), yet interconnected and complex. The layout is just slick, and the great visuals only strengthen the joy you feel when wandering around. That said, the gameplay is somewhat easy. The guards are easy to take out. By the time I triggered the alarm by breaking the glass cases protecting various trinkets, no guard was around to actually respond to it. This is where the openness becomes a (minor) detriment, something the tighter "keyhunt-ish" Hidden Agenda didn't show in this aspect. Making an (organic) sequence of room progression adds value to the later rooms you discover. Entering the tower in Hidden Agenda felt very significant, because the key you required to enter took some dedication to find, and was found pretty late into the mission. Here, you waltz through rooms without much feeling of anticipation or danger.

That said, it's something accentuated merely by other missions I recently played, and on its own, it's barely a problem and might even be preferred by some players. It's not a "flaw" really, more of a factor that plays into experiencing less standout moments in a mission. Even though this mission isn't a "standout", it's still great fun, beautifully designed and I highly recommend it (along with Hidden Agenda, please play that one first) as one of your first T2 fan missions.

Oh yeah, story. The story wasn't much special, though there's some neat touches that up the score from a regular '7' to an '8'. Nothing big, just cool extra details.