I fly a RV-4 and I often land without flaps (runways are long where I usually fly), and slipping helps me manage energy on final really well. I don't usually slip too much when I do use flaps, but it still works fine. I haven't noticed any bad habits with mine, flaps or not. I don't slow down below 65kts until I have the runway made and on short, short final. Too much sink and it gets me on the back side of the power curve and I don't like being there. Again, I'm not trying to break any records with short-field landings and I do float a bit before I settle it on. On shorter runways, a different technique would be warranted.