Seat is comfortable.

Comfortable seat

The build quality is excellent and the seat is soft without being too squishy.

The seat is thickly padded yet not too soft

The seat is comfortable, although it might seem too firm for some people

The seat is constantly sinking down.

I like the round seats and didn't want a "bicycle" style seat, or a back rest, etc

I am 220 lbs, any decent seat should be able to hold my weight.

and I have to use wd40 to loosen the joint which after a year has started to rust inside which makes it damn near impossible to pull the seat back up after it has sunk.

Solid, firm seat helps me sit upright.

However with usage of the stool, I found that I prefer it to the threaded variety since it isn't continually working it's way lower, as the threaded ones always seem to do (even after tightening the lock nut on them)The seat is pretty comfortable for a stool priced this far under $