I take it you're the reviewer. I found searching USB adapters relatively easy. John had tested and approved one, and a search turned up a few other possibilities for the second. John had thought three might be necessary, but I found one that made it work with two. But I couldn't know that until the dac arrived, which yes, means I bought more than necessary, but the cost was very small.
Direct connection not better than a $20 USB cable? You've got to be kidding! I actually tested against a $29 Pangea and a well reviewed one (Blue Dragon?) closer to $100. While it's possible that some adapters would not sound so hot, to me your statement in itself makes me wonder about your qualifications as a reviewer, however well meaning your intent. As for power adapters, if one chooses that route, John specifies a spec range, so there's not one specific set, as you imply. And if there isn't one around, they are easy to find cheap on eBay. John is upfront in discussing what's included and the options on the website. Keeps the price down. Aside from the digital output, and I'm not seeing why that's necessary, I think you made way too much of these small things.
Price: Unless the Euro has significantly increased vs. the dollar since early May, you've got the price wrong: my credit card bill shows $624 to the U.S. (no fees, VAT deducted).
Review conclusion: "Additionally, if you’re chasing bass, dynamics, and/or detail, they’re not lacking by any means, but those aspects are not the Ciúnas DAC’s strongest suit and you may do better looking elsewhere."
This conclusion is unfair to John and readers. Look where? Since you've never stated what the comparison is, except what you've heard elsewhere, quite a vague statement, it's impossible to know what the Ciunas is being compared to. $30k systems, $1000 ones, or $600 or less ones? That's a big difference. If you want to help the reader, that information is required - and better yet, some comparisons done the right way.
Look it, this was your first review. Fair enough, but decent reviews to use as a model are widely available. However, what's really dependent on the reviewer's personality or training is the ability to come at it with the (reasonable) meticulousness of a scientist. That I only see a beginning of in your review.