True Confessions?
I'm a Smartphone Addict, I am fortunate to be able to afford multiple lines and phones for fun, and staying current with iOS & Android platforms. Therefore I always have four to six different smartphones in use at any given time.
I never judge any phone based on reviews that are often biased, instead I research phones that are of interest to me, then purchase and use them for months before judging. There's nothing like owning the phone and using it in my normal day to day workflow.
I have owned and used both the X2 and Nexus 6 concurrently since their respective releases. Each has its pros and cons as one would expect. Voice commands and a "listening" phone are features that I'm not interested in. Yet for those that like that feature set, obviously the Moto has it in spades.
The Nexus 6 is my personal choice hands down. For the same reason I find my iPhone 6 Plus delightful... It's the larger spacious 6.0" display on the N6 that makes using it for my Internet Centric work and personal use, ideal. It's fast, smooth, and very reliable. A great companion to my iPhone 6 Plus.
Build quality of both my Nexus 5 & 6 models is stellar. Far better than many have reported. Therefore I'd say either the X2 or N6 are excellent choices.
My priority is getting the latest revs of the Android OS as soon as Google releases them, the Nexus 6 fulfills that objective for me without fail.