Vintage machines are generally cheap, reliable, oftentimes repairable and serviceable by the user, and can stand up well to years of heavy use. The ones still around in good shape have proven themselves worthy in a Darwinian sense. I would be surprised if a $1500 machine bought new today and packed with plastic and electronics is still around and useable 100 years from now.
A treadled machine specifically will be quiet to use, doesn't need a cord to the wall, and will work even if the power goes out. I also get more of a sense of control over the stitching with the treadle machine. My WW9 has a large, heavy balance wheel that makes stitching with hand power in tricky spots convenient and enjoyable.
DownsidesThe treadle machine can't go quite as fast as my electronic one could at full bore. Also it takes a little extra time to start and stop and to pay attention to the state of the takeup arm, etc. But I don't think the time penalty is so great and may lead to more careful execution of the work. I did rely heavily on the zigzag, needle offsets, and buttonhole attachments on the Kenmore. My Necchi BU Nova should cover all these angles, but for now I don't have a table to put it in.
The small amount of stitching I've done with my Wheeler & Wilson No. 9 indicates that it will indeed require more skill than my Kenmore electronic machine. If it gets run backwards or without cloth in the throat, there will be a tangle in the bobbin area. Stopping and starting requires some manipulation of the wheel by the right hand, and paying attention to the position of the needle and take up arm.
Tacking at beginning and end of a seam is also more tricky. I got this advice from Phyllis Rosenwinkel of Iowa, after a post of mine to the Treadle On list:
W&W did design and use reverse on some of their industrial machines, but not on the domestic ones. There are several workarounds for machines lacking reverse.
1- Turn the fabric around and begin to sew back over the seam.
2- Shorten the stitch length for the last half inch.
3- Shorten the stitch length by preventing the fabric to move easily though the dogs and foot
4- Sew to the end, Stop. Pull the fabric back 1/4 - 1/2' and restitch the seam.
The how to do this is determined by the fabric an the perceived need. I've sewed for nearly 60 years and rarely need to reinforce seams in this manner.
An excellent resource is the website Treadle On and its associated email list.