Many of my students have machines from the Bernina 300 series. They are lightweight (like you said 18-22 lbs.), but still have really good quality, a fairly large number of stitches, and other options. If you go to the Bernina website and click on the product tab, you can do a comparison of the machines as well find a number of tutorials for the various machines. You can also do a search and find the manual for the various machines. Quite honestly, I don't think you can go wrong with any of these machines. Good luck!