For me it's one of the best bits of owning a Kindle - the Kindle's there to make it easier to find time to read stuff, to think about things unrelated to the rest of the stuff I have to do & generally be more interested in the world. Foreign Affairs is great for that - a collection of essays on international relations. Okay - it's US centric, you may not like the politics (or you might, or might be indifferent) but it is one of the leading publications in the field & has some great material in it - it's worth of being thought provoking.
It's a heavy read, with essays typically 4000-5000 words. Being bi-monthly is probably a blessing in that regard. I'm loathed to mention the price, because it's a really good deal and, well, I hope the consequence of saying that out loud won't be a change!
The Kindle conversion is good... can't honestly compare it to the print version but never felt I've missed out on anything. It is, after all, a series of essays, which makes sense on the Kindle when it has to be read linearly (what you'd expect to be the stumbling block for most magazines & newspapers).
Really this should serve as an example to other 'serious journals' that Kindle publication is an option that should be available (if only the IEEE would listen) if it's done properly. One concern is that this is the type of publication where having indefinite access to back issues could be important. Not to me, but certainly to those who read this stuff seriously. As to back issues: premium subscription, or purchase copies individually in perpetuity (but keep the basic subscription cheap enough for a private individual to justify)?