I've had my sewing room in both the basement and upstairs.
I liked the basement for the summertime (and it was a HUGE room), but the rest of the year I like upstairs (in a much smaller room). I like the sun's natural light when I'm working. The basement was just too darned dark.
So my room is now back upstairs. Probably will always stay here even though it's so much smaller.
We're arid here (Idaho) so never had a need for a humidifier. I love our weather!