...it weighs a ton compared to a featherweight which is around 11 lbs (I think) but they really aren't that heavy and easy enought to move around, I can carry my 3/4 machines with one hand ...it can either be a portable machine in a carry case where it sits in the base on a table while you sew and has a cover when you aren't using it - or it can sit in a table as seen in the pic and fold away into the table. I have not seen a table extension for these machines (not saying they aren't out there) one could easily be made to fit around the base with some plexiglass...and that will probably be added to my "honey do" list! LOL
...I wouldn't hesitate taking a 3/4 machine out to a class, not sure if I would take it in the wooden case mine is in as that just adds more weight, probably see if it would fit in a rolling tote.
Joann