It's been the better part of a decade since I first worked on a Marrow Sun helmet. Sheesh. . . has it been that long??
At the time, the MS (and the Sgt. Fang) were pretty much at the top of the heap accuracy-wise. Since then, there
have been several helmets that have surpassed it in size/detail. As several people have mentioned, the FPH2 is the
new "heavy hitter" in the community. The MR helmet, the Bobamaker, and the TerminalFettler lids are some other
ones that, in my opinion, are more accurate than Jordy's good old MS line.
As far as "things that might not be as accurate" on the MS, here are some pics to illustrate. This was a build I did
in 2007. First off, the bottom of the rear panels appears slightly sunken. Whether that was due to the source helmet
or the molding process is unknown, at least to me. Also in this first pic, you can see that the curve of the outer corner
of the cheek is too pronounced. Jordy corrected this on one of his revisions.
Next, the angle of the bottom of the ear platforms (the red area) was off.
Finally, the "turn signals" on the front of the dome weren't level. The left side was noticeably closer to
the brow rim than the right side.
There might have been other issues, but those are the ones the pop into my head.
This was an MS1 by the way. I can't remember if he corrected some or all of these issues on the
MS2 or the MS3. It was a great lid, but as better reference came to light, it improved the offerings
of more recent helmet makers.