I did get the 850 kit. The helmet definitely looks much better than the older versions (I think it's basically just a modified fields now), and the armor itself seems pretty good. The lower angle of the front and center chest is ever so slightly off square, but I'm not sure that will be noticeable after assembly/weathering.
850 itself it starting to post build videos on YouTube that are somewhat helpful, as well.
I will say that knowing what I know now, I honestly would have spent the money on a 3d printer and printed either the fields or Prentice files.