It is probably better to look at each review and reviewer on an individual basis. Sure, there are reviewers out there who will try too much to please manufacturers (I am putting it mildly here), but people who buy gear can also get carried away a little too much.
I received the M11, FH7 and LC-2.5D free of charge, doesn't prevent me from writing an honest review. If there is something I don't like, I will say so in a constructive way because that is important feedback not just to people who read my reviews, but the manufacturer as well. And that is not just important, it is rewarding as well to see a manufacturer implement a change based in part (probably a very small part) on that feedback. As for the "free" gear? I sent the M11 over to Twister6 so he could answer questions from readers I can't answer and the FH7 and LC-2.5D are in storage for future comparisons.
My point is, not every reviewer cares for free gear. I have declined items considerably more expensive than the M11, the M11 was just more interesting.