My mask as arrived. I got the sierra variant.
My thoughts so far, only having tried it on in the house. Its well made, no loose threads on mine and all the stitching is immaculate. The mouth guard is well sized and covers all the vital bits.
The only criticism I have and it is a minor one, is that I wish they put a bit a curved profile into the sierra mask along the horizontal plane (red line, see image) of the mask. I've attempted to illustrate what I mean in the image below. In that mast you can see there is a curve to the mask which lets the mesh sit closer to the nose along the top.
With the sierra mask as it is, what you get is the the mesh being straight up (orange line). Its not as bad as in the image I've shown but it still protrudes outwards a bit. This leaves a bit of room on the sides where a bb could hit your hose, even with the mask bent into shape. Its not a large gap and you'd be fairly unlucky if a bb managed find that spot but its definitely possible. Not a major issue as your nostrils are well covered so it'd be a case of a strike to the fleshy part of your nose, it'll sting but nothing more I suspect.
It would also add to the comfort a bit, as if you try to shape the mask to cover the nose the mesh will start to touch and rub against the tip of your nose. Because the mesh is attached to the fabric, adding in a curve after will strain the fabric which just makes adding in the curve yourself that bit harder.
In addition to the added safety and comfort, it'd just look more gucci to have the mesh sit more flush to your face around the top of the nose when worn.
Overall, I'd give the mask a solid 8/10. It well made, comfortable and provides good protection. With the above changes it'd be 10/10.