Deep sea seals versus stuffer boxes

I fitted two deep sea seals 7 years ago to my HT27. They have dripped so badly that I have had to empty a half full bilges every two weeks. I think I read somewhere they are not recommended for drying mud berths- presumably because silt can get in and score the seal surfaces. Does anyone have traditional stuffer boxes fitted and how do they compare in performance to deep sea seals, especially if they are on a boat on a drying mud berth?
Alastair (RnR)