So you lost interest... and stopped reading completely? Had you read any further you would have realised that the unique feature is that there's both a power connector and an I2C interface available to those back covers. It's a pretty brilliant concept - you could interface with the whole host of cool chips which use I2C, or even build yourself a little robot chassis.
Power connector like the wireless chargers by Nokia etc? Not sure what a I2C interface is... My point is that I would prefer objective reviews, not glowing praise from fans etc. The key question for is not what tech did they pack in a small screen device, but does it actually feel better to use than the incumbents.
If you don't know what an I2C interface is, then you're not in a position to make the criticism that you made. If you were at all interested in expanding your knowledge, a simple google search would reveal that it's a ubiquitous serial interface for communicating with peripheral chips. All that requires more work than just blindly making critical comments on an online message board though, so why bother?
I can't believe that no pixels can be seen on a 4,5" screen with a resolution of 960x540. That would be a worse density than my > 3 year old HTC desire. A mistake in the article?
That's 330 ppi by my calculation. The iphone has the same pixel density and it is very much good. I don't see the reason to push 1080 pixels on my tiny 4.5 or even 5 inch phone.