In the 1990's, the British magazine Practical Photography was by far the best photo magazine. Packed to the gills from cover to cover. In the early part of this decade, the magazine started slipping, and one of the technical editors there, Daniel Lezano, left to edit his own magazine, Photography Monthly.
Photography Monthly quickly started looking like Practical Photography did in the 90's and literally left the new version of Practical in the dust. Funny, because once Lezano left Photography Monthly in 2006, it also started becoming a little less packed with features.
Lezano then started Digital SLR Photography
(Digital SLR Photography magazine :: Home) in 2006, which is what I consider to be the best current photography magazine. Full of informing tests and instructionals with high quality shots. It puts all US magazines to shame.
Aside from that, Photography Monthly is still decent, and actually, Practical Photography has been coming back around lately to be a very good read as well.
Bottom line is that even the worst UK mag is better than anything the US has to offer. I'd say Shutterbug may be the most decent US mag, but even that is amateurish looking compared to the British titans.
Another interesting one is Amateur Photographer, which is a weekly UK mag. Unfortunately, I don't see it carried in my area anymore. It was cheaper than the other UK mags (about $6-$7 compared to $10-$12) but it also was much smaller. However, if you take their 4 issues for the month, there's more than just one monthly issue of the others. But, you end up spending a good $25. If I was asked what UK magazine I would like a subcription to as a gift, I would probably choose Amateur Photographer, simply due to the fact that I would have something photography related to check out in the mail every week. It's content is certainly not amateurish, despite it's title, with pro level articles, info, and high level photos. I've had a few pics published there in the past, but seemed to have misplaced the issues and can't remember the years/weeks they appeared in, and there's so many!
I can't stand Popular Photography, American Photo, and Peterson's Photographic. Terrible layout, content, and photo quality. Picture is one US magazine that when it first appeared, looked as though it would stand head and shoulders above the rest, quality wise. However, if you look at recent issues, the magazine seems to have severely been dimished in size and page count, and there's nothing to it anymore. It's so small I can skim through while at the bookstore and be done with it.