Hans Punk

I just got a reply from Brian Berkey (very nice guy) - he said he does not have the exact model number for the full spec sheet to hand, but here are the important details for wiring. The Berkey motor comes with 4 bare wires for the user to solder to most common 4 pin connectors.
NEMA 14 
1A, 2.7V

Black A+
Green A-
Red B+
Blue B-
 

Cool.
Pretty sure that the Berkey motor is 12v 1amp...but I'm running it at 6v I think with no torque issues. I've contacted Brian Berkey to get a proper spec sheet. Through luck I wired a custom cable to integrate it to my Dynamic Perception NMX controller and it works perfectly. 
I cant really see if the Berkey motor is massively better than your solution, but I know that a lot of people in the motion control world use them because they are compact and can be configured in many ways... I can get the gear within 1mm of the camera body when using pancake lenses or (as seen in following pictures) when I remount lenses that have a focus gear very close to the lens mount.
Also if it can be an option to integrate into your controller and encoder, there are a few owners out there with Berkey motors on custom live action/ animation motion control rigs that would also appriciate encoder driven control that can act as a slave to rotational input. 

Cool.
Pretty sure that the Berkey motor is 12v 1amp...but I'm running it at 6v I think with no torque issues. I've contacted Brian Berkey to get a proper spec sheet. Through luck I wired a custom cable to integrate it to my Dynamic Perception NMX controller and it works perfectly. 
I cant really see if the Berkey motor is massively better than your solution, but I know that a lot of people in the motion control world use them because they are compact and can be configured in many ways... I can get the gear within 1mm of the camera body when using pancake lenses or (as seen in following pictures) when I remount lenses that have a focus gear very close to the lens mount.
Also if it can be an option to integrate into your controller and encoder, there are a few owners out there with Berkey motors on custom live action/ animation motion control rigs that would also appriciate encoder driven control that can act as a slave to rotational input. 

Introducing Rapido Single Focus Solution: http://www.rapidotechnology.com/
Test Video: https://vimeo.com/213997325
 

Hahaha. Awesome. Distributed by Western Union.

So as some already know, I recently purchased a 5D3 primarily to shoot Magic Lantern Raw. Well this week I started my first short film with it. It was definitely a learning experience but I really don't know of any camera where I would have achieved such pleasing images. I also purchased the Canon 24-70mm f/4 lens and I am consistently blown away by what a great lens it is and the OIS is so damn good, even at 70mm, that the majority of my short, thus far, has been shot handheld.
With the recent 4K Raw developments, I figured I would post some pros and cons in case somebody else is looking to pick one up.
Well the first pro is that shooting Raw could not be simpler with it. Set up Raw histogram with the overexposure hint and when it shows your color channels are starting to clip or the word "over" appears on the histogram, then just dial back your exposure a touch.
Another pro is that there are a bunch of people on this forum still shooting with the 5D3 and everybody is helpful. If you have a problem about any aspect of the process or workflow, there are plenty of other ML shooters around here that go out of their way to answer even the stupidest of my questions... not nearly as daunting as the ML forum.
Now a couple cons... you need a bunch of cards... or a computer and hard drive to offload your footage... 12 minutes on a 64GB cards gets filled quickly. Even with 3 cards, and trying to be conservative with my shots and shot ratios, I still ran out of space 3/4 of the way through my second day of shooting.
Converting the footage is a bit tedious. The RawMagic route of converting the MLV files to CDNG is fairly fast but then you still have to process the footage through Resolve or After Effects before really seeing what you have. I really like the MLRawViewer program, but although you get to preview your footage, the conversion is slow and after I updated my Mac to Sierra, the version I have does not work with it, but I believe there is a newer version,  so hopefully it will work then.
I guess that's about it for now, so I'll leave you with a couple graded screen grabs, from a couple shots I briefly messed around with yesterday...

That week of the Rangefinder debacle was one of the most memorable forum dramas of all time.