All three have a different focus. For all around coverage and general availability, Blade seems to do ok. Tactical Knives has a narrow focus, and has been accused of being too exclusive of testing by advertisers only. I noticed it, and a definite trend in common sense - really, a big four inch traditional folder will do most jobs just as good, you don't need a S30V Ti framelock like I bought. But IF you put one on the cover, test the darn thing, not give a oorah testimonial to the service that uses it. Knives Illustrated does pics well, and goes through the motions with building kits. There are others.
Internet forums cover it all, all the time, and you'll get both sides of the story, plus better access to makers, what's for sale, and the why and why not. And as you expected, you don't wait two months for your letter to be published, if at all, you got an answer within hours.
Of course, magazines are cheaper, for all that, compared to an internet ready computer and dial up, at worse. Personal logistics does have an impact.