Robyn, Welcome to the board!
That is one heck of a question. Most of the folks on this side of the board would recommend a vintage or antique machine. The modern plastic machines cost more and are WAYYYYY lower quality. I personally have more than a dozen machines that are over 120 years old that still work great. I cannot imagine that a modern machine would last more than 5-10 years without some SERIOUS maintenance.
I personally recommend a hand cranked machine for slow controlled work. A lot of people imagine that it would be harder to control with only one hand on the fabric but in fact it is the other way around.
I'll wait for lots of wiser folks to chime in on more modern options (I mostly only know about 1901 and earlier machines)