I use Microtex needles exclusively. I have a lot better luck with them with all my machines. I usually use Aurafil 50 or 60 wt thread so I use an 80/12 for piecing. For quilting I use an 80/12 or 90/14 depending on what type of thread I am using and what thickness and type of fabrics I'm quilting.
I also change needles often. My standard is to change the needle after every project (unless the project is long/large then I'll change midway). Needles are cheap compared to machine repairs.