I'd go to a Bernina dealer and see if they have any used machines they got as trade-ins.

Whatever brand you decide to buy make sure it has all the features you use and enjoy. I'm so used to my thread cutter I hate to sew on a machine without one.

I would look to see what is important to you on a machine to start with. I would put that over just shopping for the same brand that you already have. I have two homes and machines at both homes (same brand and type of machine at both places) and the trouble with sharing feet and bobbins between two places is that invariably you end up leaving a foot at one place and you are at the other. I found it was just easier to have feet and bobbins for each and just leave them there with the machine. Bobbins are so inexpensive that isn't an issue. Feet I agree can be pricy but really how many feet would you use? Probably just a 1/4", walking and general.

I have Featherweight machines and like them but they are only straight stitch. They are great for piecing but if you want to do anything zig zag you're out of luck. It also has a small harp so quilting is a challenge. I do have a walking foot for my Featherweight however.

Since you are not going to be carrying the machine back and forth weight isn't much of an issue.

I would definitely would check out used machines. I bought a good used machine when I was setting up my second home and also found a good one for my daughter-in-law who at the time had an inexpensive Singer she bought at JoAnn's that was constantly breaking.

I'd go with a featherweight. They don't take up much room and sew beautifully and are lightweight. My DH sells and services them. He was able to get me an electronic foot pedal that is like a gas pedal style that is on our modern machines. If I sew very long using the original button pedal makes my foot ache. The electronic wasn't cheap but I think it was worth it. I use a Bernina 880 here at home but take FW to classes and shipped one to CA to use at my daughter's.

My standard answer for a 2nd machine is to buy a vintage one. Featherweights are great for piecing. That's usually what I use. But I also have other vintage Singers that are way cheaper than a FW. If you're not going to be moving it back and forth, there are many heavier ones that would work well. If money is an issue, go with used or vintage.

Yes, I agree with this! I spent extra on my "travel" machine because I'm the same way - addicted to that thread cutter button.