Was it Pomona or Pomona knockoff? IME the real ones are eye-wateringly expensive but they actually work, whereas the knockoffs are dirt cheap and tend to require even more effort than soldering (between making initial contact and discovering+fixing intermittency problems).
It was Pomona-branded. They were either genuine, or very convincing-looking counterfeits. I had a few of them, and the materials and build quality seemed good, other than pin migration up that my use/abuse of them seemed to cause.
If you didn't pay upwards of $20 per piece, they were likely fakes. I have had the same experience as all the other commenters here: Pomona clips are the only ones I've found that actually work well, while all the cheap clips are just about unusably bad.
