I would try out all the machines in your area, sew on every one of them. Ask if it comes with the attachments you want. My local Bernina dealer (and I don't buy Bernina) had 17 brought in that day for repair. We were making pillowcases that day, the store provided the fabic, and I sewed on one that was used at $850 and I truly hated it. It sounded like a tractor, made out of plastic, and it seemed like I had to push on the foot pedal too much to make it go.
The main one is a White, maybe 17 yrs. old now, and I use it for everything including slipcovers, lots of cording, many layers. I would try very hard to make your machine work right. Unthread it, use a new bobbin, and make sure the needle is in right. On a scrap of fabric, sew a few inches. The top thread, if loose, means you have a problem with the bobbin area. If the bobbin thread is loose, it is the top tension or you have it threaded wrong. Make sure your needle is in correctly. Get your book out and see if the flat side of the needle is to the back or a side. It makes all the difference in the world. Since I have several machines, I put a note in the little box attached to the machine. You can write it on a piece of tape and attach that. If the threads on your scrap fabric are not meeting in the middle of the fabric, then go back over what I told you.
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