Very recent 3-wood owner/user here. I started out with it teed just above the grass from a pretty tightly mowed tee boxes. Too low. Went up to about 1/4" and was hitting line drives. Finally ended up about 1/2" lower than my driver with the ball just slightly less forward than my driver and definitely swinging up and through the ball. Great ball flight now - high and straight. Rolls out to about 200 on a good swing.
I bought the 3-wood last year because my home course has a par-3 that plays due west and usually into the wind. It plays anywhere from 188 to about 215 if tees are back. Prior to the getting the 3-wood, the longest club in my bag was a 3-hybrid that would go 170-180 with my best swing on a calm day on the long par-3 into the wind.
Once the tee was back making the hole play about 210 into a 30mph wind. Hit driver and didn't even make the front of the green! Nasty, nasty NASTY par-3 hole sometimes!