After a long term of www research i bought a rtmotion unit.
And i am very happy so far.
cost-benefit ratio is great.
The motor is pretty strong and very acurate.
The guys from RTMotion do have a good support. But as it is at every small company, sometimes you have to wait for a reply, sometimes it comes within minutes.
What i like about RTMotion is, that they are still in development and hear to your statements. And if they improve something, you can be sure to get our unit upgraded by minimal amount of money.
The problems i see:
no interchangeable marking discs (yet)
the motor is too fat (but there is a good workaround with a gear in between)
some additional benefits:
there will be another receiver which supports third party motors like Heden
USB port (i already tested a software which gives u kinda motion control abilities to the focus. ...but it's still pretty buggy)
usable for 3D Rigs
two channels (where hocus focus has just one i think) (there are just two knobs, but you can pair up to three motors i think (you can swap the second and third at the control)
I recently posted a review of the unit. It is in german, but you can check the pictures. (the gear in between lens and motor is taken from a Chrosziel Genio)