If you want absolute precision buy the Adonit Jo (or Jot Pro). There is no better one than that one).
I agree, the Bamboo stylus is very, very comfortable to sketch with, but the Adonit Jot-Pro has a best point and line precision, the only bad thing is that when I use it I try not harm the screen of the Ipad for its hard point. I just got mine, but I´m still a bamboo fan, despite the problems we have with it.