I would call the second K12 Open Minds conference a limited success. It went well enough to have another next year, but it did shrink compared to last year (like a lot of conferences, apparently, due to the economy), didn't find the kind of sponsorship we'd been hoping for, and we generally didn't solve our organizational problems. I say "we" because I was on the organizing committee and frankly, I didn't do much, so I take my share of the blame.
I think the conference has a bit of an identity crisis. Mike Huffman's vision is of an international, multidisciplinary conference -- kind of like an international EduCon with a focus on open source, openness in general. Given that EduCon is as old as Open Minds but already noticeably stronger, less may be more here, even though balancing the "ed" and "tech" in ed-tech is always an admirable goal. At least unless one can get good sponsors, but the breadth of focus on Open Mind's part makes a harder sell for sponsorship.
In practice, K12 Open Minds this year did have a fairly narrow focus: the real strength of the conference as I see it is learning about large scale Linux deployments. There wasn't much on open content, or really even open source philosophy writ large, and the educational content is pretty common stuff at conferences (if not actual classrooms).
Given a choice, I'd probably make K12 Open Minds into the premiere international conference for learning about large scale, low-cost educational computing. Which is not to say it is the only thing I care about, but I think it would make the most viable and effective conference. It is the conference that would be most likely to gain effective sponsors, draw people from around the world, and teach them things they wouldn't learn sitting at home.
There's just nothing quite like, for example, as I experienced last week, having a few folks fly up from the Brazilian state of Paraná to tell you face to face how they successfully administer 44,000 widely distributed desktops with 12 admins and a tiny budget. Go ahead and try Googling for info about it, though. I don't find anything (in English). There is no reason we couldn't put together a much simpler program of a solid day and a half of mind blowing tales of massive open source successes, and there is no reason to think we can't find some vendors to pay for it.
Alternately, or in addition, we could just move to more of an unconference for K12 open source advocates, which would achieve much of the benefit of the current conference at less cost and hassle.
Anyhow, those are my thoughts, which I don't think are representative of the rest of the organizers.