Reason I did not buy a CS 36T
The CS was on my very short list with the Niagara 35 which I did buy. A major reason for not choosing the CS was the very shallow bilge with no sump. Friends from my club went to Bermuda with one and had a good trip except that water slopped up the curve of the hull and soaked stuff in adjacent lockers. The Niagara has a very deep sump (the length of my arm when I lie on the sole).
Both boats are tough enough for offshore conditions in my opinion; both are well-built. We did Sandy Hook to Bermuda in 4 days, 8 hours in the Niagara and nothing broke. I was impressed.
As to cored hulls, if they are built properly and no one has drilled holes through the core I don't see any problem. I am not aware of any Niagaras with hull core problems except one 42 where a rub rail was installed without proper bedding. As to cored decks - almost every Niagara has core issues to a greater or lesser extent. I would imagine this would be true for other boats with balsa core decks.