First and foremost the magazine must capture your attention with a great cover and a mixture of article styles and content. I find single themed magazines less interesting than magazines that cover many styles periods and genre’s.
I also like to see great ‘eye-candy’, well painted miniatures or terrain in well set out images.
Finally for this short response. I want to see something that is going to be of practical use to me, an interesting article which I can use, a fun scenario that can be converted to my preferred game system or a tutorial that I think is worth the cover price.