I was given the 820 by my friend who loves Berninas but she did not click with the 820 . She's replaced it with the 760? the 770 without embroidery as she has a different brand of embroidery machine because she wanted something specific that brand had. She was the second owner of the machine and got it as a good deal by the original owner who was another Bernina fan who just hated it! My friend paid about half price for the machine, which was more than the trade-in the dealer offered the original owner. Lol, everyone is different and the 820 was not a popular model it has been discontinued and there are a lot of unhappy people who seem to have gotten lemon machines. She used it for several years and said it was fussy about threads, since she does do fancy things and I just quilt, I haven't had the problems she had.
Friend is very happy with the 760 and I've had the 820 in heavy use for the last year. For the most part we are doing well together but recently it's giving me an error message that I have responded to correctly. I can sew roughly 10-12 stitches, less than two inches and the error message comes up. My seam is looking lovely, everything is fine and I press the error message sew my 10-12 stitches and again it pops up. Everything sews perfect for those 10-12 stitches. I've done everything that can be done several times, needle and bobbin and thread changing, resetting the computer, basic on/off. It worked fine the night before and now it doesn't... So it's time for a servicing any way and I have my cheapo portable brother up right now.
There are things I absolutely love about the 820. The huge throat space and the lighting are terrific. Overall, it's easy to use and I've quickly grown attached to the knee lift and to stopping with the needle down by my foot control. With my vision issues, I have a hard time reading the buttons and mostly I just use the thread cut one so I know where that is! (nicely placed btw) I've had no problems with the auto needle threader, again with my vision issues that's a wonderful thing.
Now, I don't do machine embroidery but I have friends that do, and as a feature it would be important to me to be able to buy prewound bobbins. Can't do that with the 820/830. I've been wanting to try Glide thread for my bobbin and machine quilting but mostly what I find around here is prewound bobbins and it is not L, M, or 15 so haven't been able to try. I got a cone of Superior So Fine on sale and was getting nice results with that before the stitch an inch issue came up.