I do not like them at all, after trying them off and on for at least 4 years. I am lucky if I get 50% to seal. I have tried all of the posted suggestions plus a few more, including less head space, very slow cooling, various methods for tightening and re-tightening, etc. They just are not reliable and I cannot afford the time, aggravation, and potential loss of the food that I have canned. I did not like dealing with the company either, as they kept dragging things out with having me try different techniques, then refused to give me a refund when I wanted to return them. Although the Ball lids are as good as they were in the past, my seal failure with the Ball lids is still only about 1 out of 50.