are ultrasounds in a perinatal testing center the same as an ultrasound in a regular hospital/office?

In my experience the are different. I have had ultrasounds at both my regular OB and my perinatologist office. And the ultrasounds machines at my perinatologist are way more advanced. This was true for both of my high risk pregnancies.

And the techs at the perinatologist seemed to be a bit more experienced or at least more knowledgeable.

Usually the technicians in perinatal testing facilities have more training in specialized imaging techniques, compared to doctor's offices/hospitals. They may or may not have more sophisticated machines, though. Hope this helps!

The same in what way? The technology is basically the same but perinatal testing is usually more detailed.