Much like Overread up there, my experience with photography magazines has been:
Mostly adverts. So many adverts. More adverts than you can shake a monopod at. You could try shaking one at them, but you wouldn't be able to because there's just so little room because you're being cramped by adverts.
Which I would begrudgingly accept (they have to make money somehow, I don't think all that printing is cheap), were it not for the fact that there was very little in the magazines about photography itself. There are reviews out the wazoo. Cameras, lenses, tripods you name it. Which I personally don't care for, partially because I'm never going to be able to afford this $3000 lens, but also because the equipment I already have suits my purposes just fine.
The closest thing to photography are the tutorials. There are articles on composition - sorry, I mean articles on the Rule of Thirds. Because that's pretty much it. Rule of thirds. Or balance, sometimes, just to mix it up. Which is great if you've just bought the camera and are looking for some guidance but I'm not. And there are also tutorials on Photoshop or Aperture, or Lightroom or whatever. Fine, but I have a book on all that. Which I bought when I discovered that PSE didn't come with a manual (the book, funnily enough, is called The Missing Manual).
Having said that, sometimes there are 'special' editions, which focus on one area. BW photography, macrophotography, wildlife photography, and have articles about how to photograph this subject, and any editing tricks that might help. They're worth looking into on a case-by-case basis.
Now, I haven't read every magazine out there and some people have clearly had different experiences, so take my advice with a pinch of salt. Personally I just have a subscription to National Geographic.