Hey gal go for the Bernina. I agree with others, I would keep the Janome also as my back up. Who knows when you might need it. I have my good old faithful Bernina 930 that I bought new in 1985. Runs great and I love it. I have sewn many a mile on this baby. I haven't seen the 820 but I'm sure it's great. That was a gift to you, spend it on yourself sweetie. Get what you want and if there's enough left over get a cabinet for it as well if it doesn't come with one, or something else special that you wanted for quilting. Maybe a FW or a Long Arm if you don't already have either one. Whatever use it on you, and don't let it be used for general funds if you can keep from it. After all you didn't have it before, so it's not like it's going to be missed.
Just think your Aunt is giving you a great Christmas gift and an early one at that. Do this in her memory since she loved to sew. Don't ask any of the family and don't worry about or let them make you feel guilty about getting what you want. After all it's your money now.Merry Christmas!!