- they distract from the issue
- their net ratio of information transferred is bad
- cost per page of information is beyond acceptable ranges
Magazines usually cover just one or two subjects that interest you or that are helpful to your current situation. The rest is either unsolicited input or, worse still, advertisement. I don't need advertisement. Who wants to learn about the n-th version of a charting package that can be embedded into your source code or the umpteenth version management with pink color coding of source files ending with the letter x. Take away cover, index, imprint, the info per pages ratio lies somewhere around 3%.
Even if an article covers an issue right in your focus, usually the issue is large enough to be broken into several articles. Publishers do not want articles to extend two pages and they want to sell the next issue as well. So, the article consists of 30% intro and repitition, 60% information and 10% links to supportive web pages, half of them not online otherwise you would have found them in previous web searches. So the info per space ratio lies around 60%.
Your average magazine costs about € 10,- for around 60 pages. This makes 17 cent / page.
All that said, I found a magazine and an aspiring magazine that are worth reading:
dotnetpro is a magazine that concentrates on .NET software development. Much to my surprise it also covers Mono (in those much-hated multi-issued never-ending article-threads). On average, I can read 4 to 8 articles in it that interest me and the quality of code is more than acceptable.
pythonmagazine is an effort to get a Python developer magazine up and running. Issue 1 can be downloaded in PDF and offers an interesting blend of Python issues.
I am not going to change my mind: I read books, no magazines.
But I will keep an eye on the two.