I think most vintage machines are far better to sew on than new ones. Ones with lots of fancy stitches and cams, etc can't do a true straight stitch, or rather, because they're jack of all trades the are master of none.
My 'newest' machine is from around 1970 - a Brother. It has a zig-zag and I have never explored what any of the attachments and feet can do. Because I just want to sew and maybe go backwards to secure a seam.
I just spent last weekend fettling up a Singer 28K my husband found under a table at work. It has the nicest stitch I've yet seen. It dates to 1893.
My oldest machine is an 1885 Singer 12K. I have a treadle Singer 66K from 1910 and a hand crank from a similar date. And a hand-crank Pfaff from about 1902.
But my all time favourite machine and one I sew everything on - clothes, curtains and currently, a patchwork thing - is a 1956 Singer 221K 'Featherweight' which is the love of my life. It came to me fully serviced and re-wired.
Very little to go wrong on them. A contemporary machine - whether under £100 from a supermarket over over £1000 for some electronic, computerised wonder-machine... is badly built and will have a built in obsolescence. Older machines are simpler, and were engineered in Scotland so well that I can pick up and clean a 122 year old machine and have it working like the day it was made, in a couple of hours.
If you explore online you'll see there are whole blogs and sites devoted to vintage machines and they are becoming increasingly sought after.
Can you tell I like vintage machines? Clean it, oil it, change the needle and chances are you're good to go (unless you feel the electrics need checking). When today's machines are 100 years old, they will already have been 80 years plus in the landfill.