Here are some reviews, but I'm sure you won't accept those as reviews:
https://www.mobileread.com/forums/sho...05&postcount=4
https://www.mobileread.com/forums/sho...3&postcount=56
https://www.mobileread.com/forums/sho...&postcount=228
https://www.mobileread.com/forums/sho...04&postcount=1
https://www.mobileread.com/forums/sho...60&postcount=2
You find lots of this kind. I'm not really keen on looking around the forum for all reviews for you now. But if you add up all of these reviews and add mine and jbaach's, you finally get a pretty nice overview of general user experience with M92, that's at least as meaningful and independent as those user reviews at amazon.com are - and I deem them pretty helpful after all.
And "test in a reputable publication". Doesn't sound either like anything I ever saw in this world. But in my opinion, you wouldn't learn more from an "independent" review than from any other review. The only thing you can do wrong in general is believe the "conclusion" of any review out there. You should simply make a list (for you personally) of advantages and disadvantages of the device in question. You can collect those advantages and disadvantages from many reviews and usually it's not important that they are independent, it's usually enough if you have a lot of reviews.
A good review is not an independent one (because there is no such thing) but an exhaustive and thorough one that doesn't leave out any detail of the product. But in the end you don't need one such thorough review, because you can add up lots of small reviews and this serves the same purpose.