Despite how disgusting each issue may seem on tFS, I always end up buying US Vogue every month.. Out of a habit and because I love the articles more in Vogue, more varied and up-to-date. So it's definitely my first choice. As for the others...
I buy Harper's Bazaar 3 months late when bookstores drop the prices of back issues by half. And usually I just look at the editorials I love and ditch the magazine completely in the shelf. I don't read it at all. It's, well, too boring.
W has substandard eds comparable to US Vogue, doesn't fit my shelf, and is just uneasy to lug around or to even read so I only browse through it in bookstores.
Interview is too large as well. I don't bother.
V is the giantess that reigns supreme in size. I love V covers. If the cover's nice, I end up buying it despite its prohibitively expensive price... Though I only own a handful of issues because beyond the cover (and size), it's nothing special really.