A centennial 15 in good condition is a bargain for $35, and I would snap it up! Use it until you find your 201, compare, then sell the extra...or keep them both.
My current projects are being sewn up on a 15-91, and the more I use it, the more I love it. Smooth, quiet, and a powerhouse. Easily stitched through 8 layers of decorator canvas without a single balk or complaint.