I'm not a member of Worldcon this year, which is kind of a shame because I'd like to vote against the slate nominations (both Sad Puppies and Rabid Puppies), even in the instances where I might otherwise have considered a nominee (e.g., Toni Weisskopf for Editor, Long Form; Guardians of the Galaxy, Dramatic Presentation, Long Form; or Skin Game by Jim Butcher, Best Novel -- though I likely wouldn't have voted for it, at least it's not a bad nom). I've been reading the holy gods long and occasionally rancorous discussions about the noms at Making Light (if you somehow aren't aware, that's the blog run by Patrick and Teresa Nielsen Hayden of Tor Books, and several other highly knowledgeable fans and pros, and which has a commenting community that is both widely read and intelligent, partly the result of strong moderation), and think that I agree with the folks who won't vote for a slate nominee even if they think it's a worthy nomination, since slate nomination/voting distorts the spirit and tradition of the Hugo Awards (and pushes it more toward the political model, with limited choices, that we tend to see, rather than the open field that we've mostly had since they were established).
I know that other people think differently, and feel that a nominee is a nominee, and if one is worthy, then they'll vote for it. That's a valid POV, and I see where they're coming from, even if I disagree.
Some people think that the only way to counter "bad" slates is with "good" slates, and the idea scares me. I don't want to see the awards become a battleground of ideology (any more than they have been in the past).
Here are some references, with background and information. First, a post that indicates which 2015 Hugo nominees come from which slate, or none (info from a Making Light commenter): http://file770.com/?p=21708
Then the three Making Light threads on the topic, in chronological order: