Well I've been experiencing frustration with the thread tension in my free motion quilting on the Curious Kitties quilt. I'm using a new thread for me which is a good quality one from YLI made for machine quilting.

It's a beautiful seamist colour but the thread is considerably thicker than the previous threads that I have used (King Tut, Sulky, Guterman, etc.). When I was doing the stitch in the ditch portion I had no problems with the thread tension. I use a walking foot when I'm doing that task and that seems to eliminate issues with tension and slippage.
With this thicker thread and free motion quilting, I had to increase my tension a fair bit but it seemed to be a very fine line between where the settings were right for the tension on the right side of the quilt vs. the back of the quilt. When I go around curves the tension isn't quite right on the back and there doesn't seem to be a right setting to resolve that problem. It's minor, in that the person who is getting the quilt won't even know there is a problem because she doesn't sew. But none the less, I find it frustrating that I'm using this wonderful thread but it just won't behave. Hey at least it's working for the front of the quilt.
I had the machine in for servicing back in the summer but I also have been doing a lot of quilting. So once I'm done my projects for December I might take it back for another servicing to see if that might clear up my tension issues. I've had a few others issues with the tension that got resolved but it seems to keep cropping up.