My photostream is not updating
I found that I had wandered outside my Wi Fi range, and had reverted to a 3G connection.
Upon reconnecting to my Wi Fi, Photo Stream immediately updated (and I mean immediately :) I checked this by opening my Photo Stream within the Photos app, and taking a screenshot.
I noticed some of my photos starting syncing once I charged my phone beyond 20%.
Apple seriously needs to give some feedback about why Photostream isn't syncing in their UI like Dropbox does.
(Further evidence: When I open Photos on my i Device, I see the spinning icon on my i Device - IFF I've just taken a photo.