armchair or dining chair?

[Kanjejou]

yes not why and with which material you made each?

[RCMidas]

Dining chair is quicker and cheaper for the amount of resources used and the comfort it provides, making it a good early-mid game option and a highly respectable Construction skill trainer. Regular wood works just fine for this.

Armchair is better when you actually need to provide full comfort as often as possible for that extra mood buff, and whatever you use for it will work acceptably until you start a guinea pig or chinchilla breeding farm. Or, in super-long games, thrumbos.

[qualified turtle ship]

No seating for most workstations.
For eating/rec sandstone stools or with ideology the cloth kneel pillows.
Research benches & later fabrication benches/scanners get armchairs as pawns can spend all day at those stations.

They don't spend long enough at most benches or eating/rec for the marginal extra comfort to make much difference. Stone stools are cheap and don't burn, the new kneel pillows are needed anyways for ritual rooms so I combine that with dining table & rec to tipple dip on the kneel pillow use.

comfort scale
sandstone stool $31 .5
cloth kneel pillow $46 .6
wood chair $74 .7
cloth armchair $215 .8

Material choice doesn't affect comfort. If I want to drive up the impressiveness of a room it is most efficient to do it with marble walls and excellent/masterwork large marble statues.

[Astasia]

I start with stools for everything because they are cheap and fast. I usually replace the stools in the dining room with dining chairs when I upgrade it to a real dining room, because it's just wood/steel. Later I replace everything with arm chairs, usually human leather, because I need to do something with it.