I like the notches cuz they keep my thread from unraveling when not in use. To start a new spool, I simply use a needle or pin to slip under there and grab the thread end and tug it out. When sewing with them, I put the notch at the bottom, or away from the way it goes to thread my machine and I never have a problem with it snagging.
I get frustrated with the spools without a notch as the thread unwinds and gets tangled with other spools. Grrr! Sorry they give you problems.