I would ask: What do you want the machine to do? Sew a straight seam, embroider? Do you want needle up option? Feed dogs down option?
I ended up with a Bernina 1020, an older (very old now) mechanical, non-computerized, Swiss made. This works for me. And it "sews sick". If things are not just such as the humidity too high, then that Bernina will still sew a good stitch. The other machines I had would have a total fit if the thread had unraveled at all due to the humidity. They don't make these anymore and all you can hope for is a good one that has not been in a flood or a fire. Some schools had them.
I tried a computerized Bernina and gave up and sold it. .