The odd thing to me is that these guys live in San Francisco (I met most of them a few years ago). Wi-Fi is not ubiquitous here, Google Fiber will never be deployed here and most of the city only has Comcast as a real option. Their service is as good as their reputation would lead you to expect. Nextbit should know first hand that the world is not a well connected mesh of low latency, high bandwidth, and quota free connections.
The idea of loading what the phone thinks you'll need into its local storage is intriguing, and people keep trying to make it work to varying degrees. I don't think it has ever, or can ever, work simply because of the massive constraints it puts on usage. Even if the phone is right 99% of the time, the first time I need to use Google Maps and its been "uploaded" off of my phone, it's going in the trash. Just the thought that such a thing might happen and be beyond my control makes me disinclined to give it a shot (not that I would ever own an Android phone anyway, so no sale lost).
I think that devices that try to anticipate the user's wishes and plan ahead, but which may make decisions that have negative consequences, violate the user's trust. I expect technology to do what I have asked it to do -- in this case, I asked it to store something and it thought better of that.
I don't really understand their cloud storage model either. 100GB on S3 for 3 years is $99 -- not counting bandwidth and EC2 instances, which is what really racks up the bill. People aren't going to use their entire allotment all the time, but this ongoing cost is going to sink the company.