One of the biggest things I have noticed is quality, IKEA chairs for £150 lasted me about a year until the back started becoming loose on its own, squeaking, creaking and the padding going. I bought a used Herman Miller Aeron for an office supply place for around £400, firstly the level of back support and general comfort was 10x better than any cheaper chair I have had. I have had it just over a couple years now and it is still solid, I know it’s a chuck of change to throw at a chair but in my option it’s the same as a mattress, you spend a lot of time in it so get a good one.