1. It's getting wishy-washy. I don't know any campaigns that have changed around rewards this much (both pricing and what you get) and for many people that may be a turn off. Why would someone get the phone at $695 when it could go down more? Obviously the said the price won't go down but they had said that previously when they were above $700.
2. $695 immediately withdrawn from your PayPal account prior to tha campaign succeeding is a hard pill to swallow for many even if you are refunded 100% if (when?) the goal is not reached.
3. May 2014 is a pretty long time from now and I bet the wait will end up being longer (I waited almost 1.25 years for my Leap Motion and they had significant VC backing). Too many people may not be able to think this far ahead.
Why did I back the project? Well, I liked the idea of making a custom hardware device and thought crowdfunding the creation was interesting. I've never actually used Ubuntu (or Android for that matter) but the scale of the goal and the precedent it could set for people doing very capital-intensive projects with crowdfunding was what motivated me to back it.