So I finally managed to get my greasy little hands on a one of these phones after waiting awhile. I got the 64GB sandstone edition and have been playing around with it for the past week. The phone itself is built very well and it feels amazing considering how much cheaper this is compared to the Samsung Galaxy S4 or the S5. All this especially given the price of the thing $430 after tax+shipping and currency conversion.
Design: Phone is very well built and does have a bit of heft to it. Feels very solid and comfortable. The textured back and the metal trim actually give it a very premium feel relative to other phones I use. Much more of a premium feel than the Nexus 5 and Samsung GS5. Its extremely comfortable to use though is a bit big for my hands at 5.5" given I came from a Nexus 5.
Display: Very responsive and great viewing angles so far. Touch screen was responsive during the entire time I've used it. Colours on this thing are amazing.
Sound: The dual speakers on this thing are great relative to other cell phones. Love the Cyanogenmod AudioFX feature that allows you to tune how much treble, bass, etc there is as well as set different audio profiles.
Voice/Phone quality: Three microphones work as advertised and in the calls I've been it everything has come through quite well. Only issue is the "Okay Google" Google now feature is practically unusable because it only works on the bottom mike due to a software bug.
Battery life: Too early to tell but it seems quite a bit better than my Nexus 5. Only dropped 28% or so over a works day of use yesterday with fairly heavy use and high screen on time.
Cyanogenmod: Everything is stable on the release aside from a bug or two related to the mike. Love the customization options over the Nexus at the moment. Complaint so far is the broken Google Now feature, removal of the always listening voice wake feature (due to it being buggy) and the launcher not being able to easily access Google Now via swipe left like on Nexus devices.