I 've bought 8 of those, for experimental purposes.

The steel alloy, hardening and tempering is good. They take a great edge that seems to last as good as any carbon steel Dovo or other A-brand razor.
The grind is ok. Some have minimal unevenness, but nothing so severe that it conflicts with sharpening. None of my 8 shows any warp.
They are between 6/8" and 7/8" and have a smiling curve at the edge.

The blades are finished very sparingly: the tip of the spine has a hard edge, that can leave a scratch at the strop. The tang has hard edges too. Both issues are easily resolved with a small piece of 600 or finer sandpaper, or with a multiform coticule slipstone (that's how I did it).

While honing, the shoulder of the blade hits the side of the hone at a point where the heel is not entirely resting on the hone. Starting the stroke from a slight diagonal position, resolves this issue.

They scales are total crap. They are flimsy. They are sloppy attached and touch the blade while closing.

Stamps22 told me that there are other "Double Arrows" out there, that are not related to those he sells.

Bart.