I used to.
Now I have a hard time finding a class that I'm willing to spend money on.
As far as I know, most piecing now consists of sewing two pieces of fabric together with a 1/4 inch seam allowance.
Also, as far as I know, most lock stitches made by different sewing machines look a lot alike. (when the machines are working well) If someone showed me ten (straight line stitching) seams made by different machines, I probably would not be able to say "Oh, that one was sewn by a $10,000 machine and that seam was sewn on a $100 machine.
I would be able to tell you if the tension was okay and the stitches looked nice, but I would not be able to say - for sure - which machine sewed which seam.
Yes, I have been to classes where the other people seemed cliquey.
Is the purpose of attending the class to "learn something new" - or - is the purpose of trying to meet and make new friends?