Charlee

I sew on every machine I own, with a couple of exceptions. I don't use my W&W 8 treadle, because I don't want to mess up the decals on it. I don't use my mother's Kenmore because it needs repair and I haven't got to it yet. ;)
Other than that, I have a "modern" Janome that I use for quicky projects, and all of my other machines are vintage. The reasons I use them?

1. I love the straight stitch on them. Since they aren't made to zigzag, you can't throw off the straight stitch with bulky seams.
2. I love the nostalgia of them. There's just something about sewing with a vintage machine that conjures up images of those that used them before me.
3. They're quieter than my Janome! Helpful when I want to sew while William's still in bed.
4. I promised myself when I started buying vintage machines that I wouldn't have one around that I didn't use. William takes great pride in telling people that I have vintage machines "AND she USES them!".
5. You can maintain and repair them yourself without having to take them into the shop and pay expensive repair/maintenance bills.

Vintage machines have their quirks. You can't leave an electric plugged in because they're "always on". Sometimes needles are hard to find for them, and can be expensive. Hmmmmm....what else? I really can't think of anything right now... Get your old machines out and give them a chance...I'm pretty sure they'll win your heart! :)

SewExtremeSeams

The best way to know is to pick a small project and sew on it. I have a Singer 15-91 which I have yet to sew on. But, I sew on my 1951 Singer 301A all the time. It has such a straight stitch it is incredible and you wouldn't believe how fast it can go. I think I read someplace about 1100 stitches per minute... The vintage machines (pre 80s) are amazing machines. Now, I also sew on my 2004 Bernina Artista. Each have their specialties. :-D