Roland has built in a progression, each having more function and detail. He has a channel on YouTube where you can follow his progress over the last couple of years.
I went with the 3.1 specifically due the ability to have a spotting camera and a shooting camera via a switch by the trigger. I also included a DVR so my son and I could record our activities. Roland did a fantastic job building this rig. You can see plastic welds etc.. where he meticulously thought of every need, especially for me and my one handed shooting. I'm very happy with this setup, even with the cost. I agree it is not for everyone, but it's perfect for me.
Lastly I am hoping Roland joins this forum so he can answer these questions himself

(I don't want to speak for him, but I do want to support him)
2.0 uses Goggles and a single camera along with a traditional Scope.
Here is the 2.0 Build Link:
Here is the 3.0 Build Link:
Here is a link to the 3.1 Build (No DVR):
Here is a link to the Parts list, it's slightly outdated but it works:
Link Burris Rings (Critical for Zeroing):
Link Link2 Mike