We've worked on a couple custom speakers using the Purifi 6.5" paper woofer.
Matter of fact, one was here just a couple weeks ago, paired with one of our Neo 3s in a custom waveguide. Turned out quite well.
They were well behaved woofers, but I've yet to hear anything that uses them, and we haven't looked at any of their other woofers yet either.
The speaker design is certainly well braced with large, smooth round overs and thick cabinet walls with lots of braces. Should do a good job controlling for internal resonances and eliminate any diffraction, but there's definitely going to be either an external crossover, or more likely, digitally controlled by the amplifier using a digital crossover/DSP.
I'd be curious, to hear it for what it is.