I loved my modern Bernina 820 when it ran, but it quickly got the nickname Cranky Bernie. I was it's 3rd owner -- the first 2 owners still believe in Bernina as a brand and are still using Berninas, but I will not. I don't have any really brand loyalty and am considering a new machine of many brands, but no Berninas. The first owner bought it at full price but took just a little too long to decide she didn't like it. The shop refused to give her even a 50% trade in on the basically new machine. My friend bought it from her at half price and found it was just too fussy and non-reliable. She gave it to me after a couple of years.
My BFF inherited her MiL's original 830 and is very happy with it. In general, those seem to be super machines but they reused the numbers and nobody seems thrilled with the computerized versions. There are many many angry web comments and reviews. Bernina came out later with admitting they made bad design decisions they were reversing and not every doing again, and that they did have some quality control issues. But, haha, joke's on you for spending 10kish for a sewing machine!
In the 7 years or so that I had Cranky Bernie it was out for repair roughly 1 full year. That doesn't include the year the shop was closed for Covid. Each repair/maintenance cost roughly $300. I replaced the top thread sensor twice. The third time it broke and pieces fell on my sewing the shop paid for it, since the paid repair lasted less than a month This last time the bobbin thread sensor went and then the top sensor went again. I can run out of bobbin thread just fine, but the machine seemed to be set for how long a period I could ignore it, and the top sensor shuts the machine down even if it could sew 4 stitches at a time perfectly...
There is a thing called the "sunk cost fallacy". I'm walking away, not putting another dime/another month into trying to get it fixed again because it just didn't stay fixed. I don't like the attitude or customer service I received.. But the reality is for $300 per repair, I can just go to Walmart or Joann and buy a brand new in the box Brother and be up and running again in minutes instead of weeks. For the thousand or so it cost for the repairs, I can find a number of other options. Sure, machines with plastic parts will wear out with daily hard use, but then I can just buy another one.
I have narrowed down the features I want. Right now I'm using my Sparrow 15 I bought as a portable machine, and my vintage Remington that is older than I am. I've had it for over 30 years and it's cost me somewhere less than $200 for one repair/cleaning and a couple of the rubberized bands and a replacement foot pedal.