I have tried different things. My problem seems to be with the medium and small alphabets. I don't think I noticed a big difference with the pictures so much, but I am considering changing to Isacord. It seems to work better with the small and medium alphabets.
I seem to do fine, then it messes up. I try to check out everything, rethread top and bottom thread and all that, check for lint. Embroider and it may work fine, may not. Can leave it for a day or so, come back and it might work fine. I only seem to have the problem on the two alphas. Took it to the repairman, he has looked at it, adjusted the tension and it works fine...for a short time. ugh.....
and I now have 100 spools of metro....