I have a GGI chair which I bought 20 years ago for £95 which has followed me to multiple properties and I’m still using today. I don’t know if they still produce the same model – the label is so faded I can’t read the number! – but I would buy their brand again.
I have also heard good things about Herman Miller from people I trust – one thing I was told was to make sure to get the right size as they have a few options and it depends on your build. Not sure I would be comfortable buying one until I’m able to try one out, either in a shop or on a home trial.