This has really helped me to sew straight lines -
I cut it so I don't have to remove anything to change bobbins. Had it on for several months now and sure love it, as it also takes care of that little bump from the throat plate that gave me occasional grief.
I can untape the part on the machine and leave the rest taped to the extension table, remove the table and do any maintenance on the machine. Then put the bed back and retape the part on the machine and I'm good to go!
I have it cut very close to the feed dogs, and have not had any feeding problems since putting it on. It's really helped with HST and flying geese too.