The Rocca has a completely different head design than the DE89/R89 razors. In practice I would say that it is more efficient and also has more blade feel. It is one of my favorite razors, partly because I love the birch bark handle. That said, the razors I use most are the Karve Christopher Bradley with the G plate and a Blackland Dart (no longer manufactured). Both of those are more efficient and have more blade feel than the Rocca.How does the Muhle Rocca differ from the DE89/R89 heads?