In thinking about it.... I probably should mention:
There are many folks who sew quilts on some of the other old black type Singers: usually 66-16s, 201s and even the industrial black singer 31-15's. They each have their merits.
Some sew quilts on the newer 301's (the er...'big' featherweight) or the slant needle machines (400s, 500s, etc.). Those I would not recommend for FMQ. For piecing tops, they are great.
The 301's and the newer 400/500/600 series machines, many of them... were made from cast aluminum, not cast iron. So they weight much much less. The gearing is not as tough as the older machines, so the torque in sewing seems to be less. Aka less piercing power. At least, that is my experience with them.
I have a 66-6 (straight stitch only), a 301 and a 403 (slant needle zig zag/decorator stitches with cams), and both I use for piecing, dress making, home dec and stuff like that. They are good machines, and none of them cost me over $150, even including the cabinets, chairs, extra parts/accessories. The 403 uses cams for zig zag and other specialty/decorative stitches. The slant needle machines give you more of a view while sewing... that can be a big plus when I'm paper piecing a compass or other triangular bits.
Check out the Vintage Sewing Machine Shoppe section of this board, and you'll find a lot of people doing quilting on the old machines ... and why. Lot's of good information.