At first I was annoyed that I had to lose the physical keyboard for screen tapping. My texting speed dropped horribly, even with the return of predictive typing (which you don't need when you hit actual keys). It felt like a major step backward.
In the last couple days I've been using something on the phone that runs rings around typing: voice recognition. I assumed I would have to set it up to recognize my voice and all the other stuff I never bothered to do on my previous two smart phones. Instead, this is Google: I speak at dictation pace and it gets all the words right on the first try! All of the sudden, touching the phone is for babies.
Speaking of hands-free: While I was back east during the first week of May, I rented a pretty sweet car (the upgrade was $20 for the week and the fuel efficiency made up for that tiny change). It had a Bluetooth setup that blew my mind: you took a couple minutes to name the phone you were syncing and learn a few commands. After that I could press a button on the steering wheel, say "call, last dialed" and I was talking to my wife. The phone and the car were thick friends. It even potted down the radio when I had an incoming call.
One disadvantage that remains comes from the phone being purely in Google's hands instead of T-Mobile's. My previous phones had wifi calling built in: if I had a WiFi connection, I could call VoIP using my phone and it went through T-Mobile's network. Since I have unlimited US calling, this meant I could take and make calls as if I were back home -- no extra fees. This was a life-saver when I was in Europe or Canada.
I assumed all smart phones did this. It turns out T-Mobile's app for this is deeply tied to SIM card recognition -- so deeply that they don't bother upgrading their software for newer versions of Android. This also explains why I had many apps that could not upgrade on my old phones: if I had upgraded from the specialized version of Android on that phone, I would lose the feature.
This means my new, sweet, 4G LTE, pimptastic, make it rain, hard core, bytchyn, boy do I love it phone (which matches my Nexus 7 tablet -- no human retraining period required) will need me to set up a Google Voice line for a VoIP/wifi backup. Then again, that's a chance to pick a cool number.
That's really the only residual disadvantage. The Nexus 5 is like having the monolithic plinth in my pocket. I can sit on the train or in line at the supermarket reading books without carrying anything else with me. New version of Android? I get upgraded instantly. Things turn on and off quickly. As with any smart phone, the actual phone part is sluggish -- I told you to dial, so why has it been five to ten seconds and I still don't hear a ring?
One other cool thing is T-Mobile does provide its monitoring tools. Normally I use them to pay the phone bill from the phone and to remember to reboot once a week. However it can also tell me which features are draining the battery, which led me to learn how to disable AGPS location services with the same 1-2-3 ease of toggling Bluetooth or WiFi. I can suddenly go many more days without recharging.
-later I'll tell you about the competition I won, Ps/d