The Paradigm Persona sub drivers likely have relatively little xmax compared to the No.25. That extra cone surface area might not be able to make up the difference. And the Persona drivers are certainly going to have a higher Fs. Yeah, the No.25 is expensive but it is dead sexy. I wouldn't mind having a pair. Or a pair of stacks of three.
As for value, this is a luxury, high ticket item. It operates on a different market plane than high value item like Hsu or SVS. It's like Rolex; sure, you can get a more accurate timepiece with a $50 Casio, but no one is buying Rolex watches so they can know what time it is.