2140 Machines can be upgraded to 2170 as can the 2144. I've had both and they are extremely alike save for bobbin winding. Pfaff did issue a fix for the bobbin winder on the 2140. You need to check.
I like my 2144. It does sew on almost everything.
While I can FMQ, the Pfaff does the sashing. I don't feel comfortable with FMQ that small an area. Since I do QAYG, stitching down the sashing does give extra hold to the joins in the batting.