I use their electric standing desk, a Desktopia Pro model. It’s really good. Initially, I had to get several returns and re-deliveries of the bamboo desktop, as they never managed to deliver wood that was free from scratches or machine damage. They acted very well during the process and in the end I got a perfect product.
I also got one of their Ergohuman Plus chairs (not sold any more, as it seems). It’s very good quality, but the head rest is too far to the front if you have an erect spine. You can see the same in product pictures of their current chairs. I can’t really rest back my head (especially in reclined position) as the headrest keeps me in a rounded, hunched position. Note that this might not be the same for other people - I have a lot of ballet training and used to be a professional dancer. The chair might be perfect for “normal”, slightly hunched people.
No idea about their chairs, but I built my pc in a Fractal North case last year. Absolutely love it.