There are things I like about either machine so it is a hard choice to only have one of them. The 15 is easier to clean out a thread nest in the bobbin area. Either one is a powerful machine. Either one does great stitches and are well made. Being someone who sets up two machines to sew - just get one of each... The bobbins don't interchange but the attachments do. If you have another machine choose the one that the bobbins interchange. The 15 uses class 15 bobbins and the 201 uses class 66 bobbins.