We purchased two of the Union Scale FlexFit chairs (one black one blue) prior to buying a red/maroon one for a close friend. These chairs are--in a word--AWESOME!! For back pain sufferers these are truly ergonomically comfy. Aesthetically pleasing in overall design and color. An invaluable asset to any business or home office.
The Hyken chair requires significant "customization" after assembly to make it even reasonably comfortable. Mesh seat: I weigh 150 pounds but the mesh sinks when I sit on it. It's like sitting in a deep hole and is bad for the hips and spine. I had to insert a large foam cushion AND a gel cushion between the mesh and underlying plastic frame to make it passably ergonomic. Lumbar support: Digs into my back. Had to insert an extra foam cushion between the lumbar support and the mesh on the back of the chair. Also had to duct tape the support to keep it from sliding up and down during use. It doesn't stay in place. Headrest: Had to tilt my head too far back to use it. To make it usable I had to attached a car seat neck pillow to the front. Also the mounting holes and bolt channels on the back are misaligned. I have to periodically retighten the bolts to keep the headrest from falling off the chair. Purchasing this chair was a "test run" to see if it would be worth buying 30 more for my workplace. It looks nice. But it's poorly designed and sloppily constructed even for the price. I definitely won't buy another and I doubt this one will last more than a few years.
Decent chair with the mesh. Unfortunately with my torso the neck rest is too low and prevents me from sitting all the way back comfortably. Problem could be fixed by raising the back by 2 inches or raising the neck rest by the same amount. Neither is an option. The lumbar support is sharp on the sides. After some time of sitting it gets really painful.
The best chair ever. I first purchased this chair for work in 2016 and have since purchased 5 more out of necessity and quality. After 6 years of use the first one has started to shrink on its own but that's not bad. The best chair for sitting all day and helps with having a bad back.