Suger marks are small reddish brown needle or hair looking things, and when cut through the center can be a squigly looking line that is the same color. I find these no problem at all, not even asthetically. Shafts are made of sugar maple, and therefore if it has no sugar signs in the wood it's possibly something to worry about. Shafts that show good sugar is a sign of a healthy tree, and therefore a resiliant & stable piece of wood. Vacuum drying the wood cooks the suger out of the wood, leaving it very white & clean looking. In this circumstance, which is becoming common nowadays, it's making it extremely tough to identify unhealthy wood because it looks exactly the same as the healthy stuff. Vacuum drying makes for "pretty" shafts but I still prefer the traditional kiln dried wood.
The ugly marks that are distracting are mineral marks. They can be green or black or very dark brown. They are very pronounced & stand out. They are distracting even for me, who actually prefers ugly brown shaft wood. The mineral stain comes from the tree growing in mineral rich soil. Often times people get the two types of marks mixed up, and call everything a sugar stain. But actually the sugar stains are light brown/red & the mineral marks are dark colored & blotchy.
