Looking at it, my favorite part has to be the physical volume control buttons.
Before I started using an LOD Cable and Amp with my Nano (5th Gen), I'd always turn on the Hold Switch, so if I wanted to change the volume, I'd have to turn off the Hold Switch, change the volume with the Click Wheel, and then turn on the Hold Switch again.
In a way, it seems like a combination of the 5th and 6th Gen Nanos. The (relative) form factor of the 5th Gen with the Touch Screen Capabilities of the 6th Gen.
Disappointed that there is only a 16GB model, that Apple dropped the 30 Pin Connector and replaced it with the "Lightning" Connector, and they didn't add a camera like they did with the 5th Gen.
My music collection is about ~13GB so my current iPod Nano (16GB) is almost full... Wish they made a 32GB model. I might end up upgrading to an iPod Classic which would hopefully last me awhile. 
Not to mention the fact that I won't be able to use my LOD Cable anymore (therefore preventing me from using my Amp).
Could care less about it lacking a camera though... never really used it on the 5th Gen anyway.
Just curious, why did they make the "Home Button" a Circle instead of the normal Square...?