I find the best straight stitching are the vintage that only sew straight stitches.

I did a comparison of my Babylock Ellisimo Gold and my 1920 Jones Family Hand Crank machine. Both were great,the vintage straight stitch was just a tad better.

I love and use my 1957 Singer 401A for most all of my sewing. I do use my FW for small repair jobs and I own a many years old Viking machine also. It sews beautifully.

I can absolutely tell the difference between straight stitches made on my Bernina and those made on my Janome or even FW. Newer 9mm Bernina (and horizontal bobbin) may make a stitch that looks a little more serpentine ; I'm not sure.