Fantastic engineering and build quality let down by a singular poor design choice. - Wilcox AN/PVS-14 Arm Mount with NVG Interface Shoe

The bad:
I only have one compliant, but it's a very significant one - because the arm is straight instead of angling the monocular back towards the users eye, it massively increases eye relief. Even with the mount run all the way back, there's still approximately an inch between the eye cup and my brow. The distance costs you a bit of FOV too - if I had to guess I'd say 5-10 degrees. I'm leading with this because I simply did not consider that it might be a problem. The model with an on/off switch does have an angle like a traditional J-Arm, so I'm wholeheartedly recommending that for the reasons below.

The good:
As one would expect for the price, the build quality is fantastic. When locked in either position there's absolutely zero play in the joints, and the bayonet mount is extremely secure. Additionally, the thumb-screw you use to align the monocular to your eye is separate from the button that unlocks the arm to switch eyes. The practical upshot of this is that it "returns to zero" very easily, with no fiddling or adjustment required.

In summary:
I struggle to call it anything worse than "Not fit for purpose." If it were angled to the rear have nothing but glowing things to say, but this ultimately my failure to consider the implications of a straight vs angled arm. Spend the extra 20 bucks and get the on/off version.