I bought my Bernina 830 4 years ago. For the first two years my thread kept breaking. I was so frustrated! My dealer is 2 1/2 hours away, so it's hard to go to him when I need to. Well, I finally took it to him with the thread on it that kept breaking and he chuckled and grabbed a 100 needle and put it on and NO MORE BREAKING!!! He told me the thread was too thick for a 70 needle. Fixed my problem right up. I haven't had any other problems with my 830 other than that and that was owner error completely. Now I use 50 wt. Prescencia thread on a cone with a 70 needle. It works just fine.
I haven't used the embroidery except in class at my dealer's shop. It works perfectly great! But that's at their shop. Now when I have to do it at home, I might have a little trouble. But my 830 has behaved well for me. I'm so glad I bought her!