Also, use way less mask points PlainDawg and always mask body parts, so mask around just the head and one mask for just the body...if the person moves his arms too, mask left arm, right arm, left hand, right hand...but looks like he might be only moving his head?
Thanks for mentioning my MaskTracker+ :-)
If you need such an accurate mask, the tracker probably won't give you a 100% accurate result. But tracking the mask and then adding some manual keyframes for fine tuning can work.
See this tutorial:
It also helps to have separate masks for parts that move independently (one for the head, one for the arm etc).
Alternatively, you can test whether the Roto Brush gives you better results.
Also, mocha (maybe combined with Refine Edge tool) could be an alternative.
I show both the RotoBrush and mocha workflows in this tutorial:
Rotobrush is your tool, not roto by hand. Be sure that you go through a couple of tutorials before you start because the Rotobrush tool is not very intuitive and you'll fail if you don't study up.
Second suggestion, only roto the frames you need to fix. Do this by splitting up the clip so you don't spend a single minute doing roto work that is not needed.
Thank you all for the good suggestions. After some testing I got the best result from the rotobrushing. Now I just need some coffee and a large dose of patience