We have them on twin engine vessel that was re-powered recently. Traditional stuffing boxes were removed, Norscot were put in..
overall, good results. Nice not having to deal with cooling water.
At one point we were losing oil on the starboard, I adjusted the seal by moving it 1/2" aft, seemed to do the trick. I mostly attribute to the shaft not the seal.
We are running vegetable oil in them, not ATF