I am filling in dips and cracks on a rosewood fretboard. While it does sand well, It does not take stain,paint or tint well, cause if You try to file and sand a fret stain or tint comes right off, which strips the putty. The putty does set up fast though.
This wood putty sets up soft, so it is good for gouges that are surrounded by good wood, but not near unsupported damage. However, it takes stain better than any other I have used. I even successfully used it to repair damage on a door surface which had to have the stain matched.
I wish this wood filler could solidify more... But it's a pretty good filler nonetheless.