I bought the Bernina 770 with embroidery a year and a half ago, and I just love it. Recently I bought the Bernina 570, and love that one just as much! The one thing about the Bernina sewing machines, they require a lot of oil. My new habit has become to oil and clean my machine every time I start to sew for the day. I have noticed that if I don't, it will start to sew crazy. In addition, I reapply oil after about every 2 hours of sewing.
I know that seems like a lot of oiling, but it really makes a huge difference. I learned this from watching those "Bernina Jeff" videos. He really goes over lots of details of keeping your sewing machine happy.
https://m.youtube.com/watch?v=ePh-12I6Oy0
Another good source for online information is Heirloom Creation sewing mastery videos. Amazing information! There isn't a whole lot of difference between the770 and the 570, so I would absolutely watch the videos on the 770. You will be amazed at what you will learn!
https://sewingmastery.com/bernina-770/