Count me on the "hate Bernina" list. My Bernina ALWAYS had an issue when it came to TENSION, threads and needles! Today it will sew, tomorrow the tension is off and ANY fabric is a problem!!
I hated my Bernina so much, I gave it to my sister and bought myself an Elna 740. Never a problem with the tension and it always sews....no matter the thread or the needle ....it just sews purringly soft whenever I turn it on.