I have a 27 and a 66. Treadling is the same on either. I like the 27 for piecing, since I can fill several bobbins at once, and am less likely to run out. The bobbin in the 66 is round and holds more thread than the long shuttle bobbin. Both sew beautiful seams. I think I'd get both and swap the heads out until you get the urge to work on the "bad" cabinet. Good luck and happy treadling!