mocha will make jitter free shapes from frame to frame, and you will be able to
draw shapes having multiple custom feather values per point in the mask.
Rotobrush i think needs lots of improvements. Maybe in the future will be ok.
By using mocha you will also have the tracking data as a handy tool.
But if rotobrush works better for you, well maybe you should precompose the rotobrush result,
and then try to autotrace this result to make some further adjustable mask.
But this isn’t what i really recommend.
In many cases will create tons of extra masks for the scenario of crossing hands, fingers etc. Sounds like roto x2 without better results.
maybe you should try Silhouette Roto as Ted recommends.
I ran a demo a few years ago.
It was kinda tricky with no any web training resources.
Keep in mind also the price.