I have found that the Singer plastic bobbins (Class 66) work well in my machines -- no problems at all (unless I happen to step on one that's fallen to the floor. I have three machines that take Class 66, my 328, my 201 and my 403A. I have NOT used any other make of the plastic bobbins, but I've been using the Singers for more than 30 years, not an endorsement necessarily -- just a statement of fact. I've had NO problems with them.
Jeanette