Can't seems to find anything specific about Wasabi uses ZFS on Google. And Wasabi doesn't change you on egress. So I guess they are similar in terms of pricing.
Although B2 seems to be way more popular on HN. I rarely see Wasabi here.
There is the testimonial on Klara Systems’ website:
"The developers at Klara Inc. have been outstanding in helping Wasabi resolve ZFS issues and improve performance. Their understanding of ZFS internals is unmatched anywhere in the industry" - Jeff Flowers, CTO, Wasabi Technologies
Book price is $6.99/TB for Wasabi vs $6/TB for Backblaze. Wasabi charges 90 days minimum for storage, and egress bandwidth is limited (honor system) to your total monthly data storage amount.
Wasabi also requires you to pay for a minimum of 1TB, whereas B2 charges per GB. That doesn't really matter for a company using a ton of storage, but it does for my personal use case of a few tens of GB.
You won’t, however, be able to serve most e.g. media files or binaries this way, nor serve to clients like mobile apps, while staying within the bounds of Cloudflare’s terms for their free and “self-serve” tier paid accounts.
(Unless something’s changed since the last time I checked)