My son will probably post on this as he has one, but my impression is that he is very satisfied. I've handled it, looks like a Cadilac compared to a SAR.
Since I've been set up, here's my take on the Hesse-converted Saigas.
The work that Hesse does on the Saigas consists of the following:
-Replace furniture with US-made stuff.
-Add an AK-74 style muzzle brake.
-Replace the fire control group with US made parts.
-Add a feed ramp.
-For some reason, they milled off the lug that allows you to keep the cleaning rod under the barrel.
Most of the parts and the exterior finish are original Saiga, i.e., excellent. It is FAR superior to that on any of the four SAR-1s that I, Ron in PA (AKA Dad) and my brother have owned. OTH, it doesn't work any better than the SARs -- those are crudely finished but very reliable guns.
So far I've only put a couple hundred rounds through it, but it worked flawlessly. Since the bulk of the parts are original, you don't have to worry too much about Hesse's generally poor quality. Based on their poor reputation, I wouldn't buy a gun they made from the ground up. However, getting the Saiga modified by them was an affordable way for me to get an AK-103 clone at a reasonable price.