I have used Scubapro Mk 2's and Mk 16's with no issues on ice dives and in very cold water (33-35 degrees) at depths to 150 ft with no problems. Their TIS kits do an excellent job with no extra maintenence and nor concerns about diaphragms or seals potentially leaking and negating the effectiveness of an environmental kit.
The older SPEC equipped Mk 5, Mk 10, Mk 10 Plus, Mk 15 and Mk 20 were also very reliable for ice diving, but the latest TIS equipped Mk 25 has some issues in cold water as it just does not work with 100% reliability on the Mk 25.
The discontinued Scubapro D400 was an excellent second stage for ice diving as were any of their metal cased second stages due to the superior heat transfer traits they posessed. The current G250 does very well in cold water as do the R190 and R390.
I have used Conshelf Supremes in the distant past and they work very well until the seal and the fluid behind it leaks out. At that point you have issues with the reg potentially freezing after water enters the ambient chamber and worse, corrosion almost always occurs in this area as the water is trapped with no place to go and no way to dry between dives. There is nothing about the Titan Supreme design that strikes me as being much different in this regard.
This is a concern with any design that uses silicone grease, oil or alcohol for antifreeze protection - they have to be maintained and checked to ensure they are still topped off and leak free.
Sherwood's design which uses as small amount of air constantly bleeding into the ambient chamber to keep it dry is a good one and like the SP TIS kits has the advantage of simplicity and low maintenence. One possible downside is that a very rapid descent can exceeed the capacity of the system to keep the ambient pressure chamber full of air.
