I tend to brew more intuitively. When I bought BS for my tablet, I never liked the interface, and it seemed really clunky. I have no idea about the true efficiency of my rig. I generally guess at about 70-75%. For recipe formulation I use tastybrew.com, they have a really simple full recipe calculator that gets me into the ballpark for grains and hops. I guess it would be nice to have a strike water calc because I am always guessing and adjusting to get the mash temp right. At sometime in the future I may buy the PC version, but I need to get a PC first. LOL