i have the designer se le...one of the cons of it is it is not as quite as some of the other machines,especially when i do embroidery one it. It does get a little more noisy when it is threaded wrong, right before it yells at me to check the upper thread. And yes the only thing you can do on these machines is to clean the bobbin case. I think because you don't ever have to oil them. Other then the noise i love my machine. Hope this helps.