Let's face it. Microsoft released a Professional product with an average pen/stylus. Problems with jitter, tapering, hover lag etc, makes Surface Pro 4 look weak for professional use by artists. They jitter especially is a known issue that becomes more apparent when drawing slowly. I did a quick test of removing the nib and putting it back halfway in. Pen still works and registers pressure, but the jitter increased. It's clear that the field from the active pen is too weak for the digitizer to pick up, hence the "jitter", as it's trying to guess or triangulate the pen from a weaker field. A drained battery also increases jitter. Microsoft has the advantage of using an active pen on a passive digitizer so they have every opportunity to release better pens for professional use, with stronger fields, but maybe with less battery life. Would you pay for a professional more accurate pen if they released one?