Looking for brake rotors for my 70 cuda convertible. I found the 1 piece power stop rotors Anybody use them or is there a different alternative.

Good luck and tread carefully. Maybe buy one first just to see how it checks out. Aftermarket parts for the non-popular applications aren't always high quality.

Maybe consider getting the adapter sleeve for the spindle so you can use the later model rotors.
Many more choices

I have the centric version on my car for many years, though low miles. No issues.

Same here, I've used the Unicast rotors that are available for years on different cars through the years and never had a problem.
They're cheaper than the Powerstop rotors but if you're looking for more of a performance option that would be the Powerstop since they're drilled and slotted.