To be a bit of a devil's advocate. Don't know how well or otherwise the Dust Deputy works, but without working through the minutiae the unit in the photo looks like a decent fabrication. The inlet is probably stitch welded the way it is to avoid distortion, and should seal up easily enough.
If it's accurately to a set of dimensions that work, then it's surely not a bad deal - even if it is made locally.
'Works' can be a bit of a broad church, in that it's not hard to drop out the chips, but the very fine (dangerous) dust is another matter. Establishing this ideally needs testing the exhaust with a dust particle counter, so if it was me I'd be looking for evidence of this having been done. Since many of these particles are pretty much invisible the average punter saying their unit is great may not amount to this.
Some of the Oneida units are vertically a bit shorter than some would recommend, and the round inlet is said by some to be less than optimum too - but then you hear many positive reports about their stuff. The same goes for the Thien trash can separators.
Maybe the core issue is not so much the fabrication as this question of how well they work on fine dust (so that there is minimal carry over into the filters and out into the shop). It'd be nice if there was some independent test certification available, but even if there isn't they do seem to sell quite a few....