Jeff, if you're so inclined, have you seen much sales with your books from the more niche PD sellers like Dreame, the Chinese retailers or any other?
No. I use Amazon, Kobo, and D2D for the major retailers, so I only use PD for the niche ones that aren't available at D2D. Some of those niche retailers don't accept English-language books, so I'm obviously not on them. PD is a Hungarian company, and at least one of the retailers is for Hungarian-language books only. Some Chinese-language-only stores, too, if I recall correctly.
I had a few page reads--or whatever--from Dreame a while back, but that was just a one-time blip. The only other money I've made from PD is when I first opened the account and had my books on Google Play.
For the record, I've never reached the payment threshold, so what few bucks I've made are still with PD. I probably won't see that money until I close the account.
PD just recently partnered with iReader, a mobile reading app, and they sent my books there. It seems geared for romance readers, though, and it serves Southeast Asia, and my books are written in English, so...

Needless to say, my expectations are zero.
One would think that the smaller book selection at the various niche stores would make it easier for the books that
are there to make sales, but that hasn't been my experience. I have no idea what it takes to make sales at those niche stores.
For me, their niche retailers would be the only goodies that would attract me. I already use Smashwords and D2D. To charge for a service, PD would have to make the retailers they use outside of D2D and Smashwords viable. Otherwise, their royalty base is not inviting with the $69 lifetime fee. I'd argue, if you're an established author, it's honestly gonna be hard to make $69 from those extra vendors alone (the other retailers are free with D2D, Smashwords--even Streetlib--otherwise).
I agree with all of this. D2D is easy, reliable, free, and has stellar customer service. They're constantly adding new goodies, too, and they do it
without totally revamping the site, something I really appreciate. For years now I've considered them the gold standard for distributors, and I still think that.
...D2D is at least responsive with price changes and working with publishers. How is PD? I don't have the experience, so anyone with experience jumping in would be appreciated.
When I published my books there, I experienced a glitch on one of the retailer's product pages. The paragraph breaks I put in my blurbs weren't translating to the product page, so the text was all mashed together. I contacted PD about it, and they fixed it promptly.
So I'm pleased with their customer service.