We have had our new iPhones over a week now. For the record, my wife and I moved from the iPhone 5, and my in-laws moved from the iPhone 5c. We're a few days away from AT&T's ETF fees, which will then be passed on to T-Mobile to reimburse; and our old phones have been sent to T-Mobile as a trade-in. Yes, you can sell your phone yourself, but we expected to only get $250 at best for our old iPhone 5 models, and my in-law's iPhone 5c models were still locked under contract. Easier just to trade them all in for just a few dollars less (this is the truth).
T-Mobile has offered decent coverage; yes, blazing fast LTE is limited to the metro area (my iPhone recorded a speed test of over 35 Mbps while on LTE in the Twin Cities area, which is faster than my 24 Mbps router at home, or the 11 Mbps LTE coverage near our house). Otherwise, we seem to have cell coverage–and no coverage–in the same areas that we experience with AT&T. But when you have that T-Mobile LTE…it is INCREDIBLY faster than AT&T (which incidentally scored 5 Mbps just a day before we moved to T-Mobile).
As for the devices, they are simply the nicest phones we have ever owned. I like the curved edges; I love Touch ID; Siri is much improved in iOS 8 (I find myself composing many e-mails through Siri); The larger screen of the iPhone 6 is practically bigger, not “terribly” bigger (we aren't 6 Plus people); The camera is great; and battery life is better than our iPhone 5 models. I have no issues with the new location of the power switch, and wi-fi calling has been fantastic (working in a school where there are places without cell service, but ubiqutious wi-fi). I know a lot of people were excited for the ability to use custom keyboards with iOS 8, but I don't have a single non-stock keyboard installed.
Even iOS 8 seems to work better on my iPhone 6 than on my iPad (4th Generation). This is iPad replacement year for me (supposedly, new models are going to be introduced on October 16), so that doesn't bother me too much, but I do hope that Apple irons out the bugs in iOS 8 soon for the sake of our 1:1 which is populated with all 4th Generation iPads.
Should YOU buy an iPhone 6? Well, if you are an iPhone/iPod Touch/iPad person, and you are up for a new phone, absolutely. If you have no allegiance, then (insert shocked sound), I don't think you can go wrong with any of the top-of-the-line Android phone, either. Here's the deal: you will find that you use your phone for specific tasks. This includes (for us) calls, FaceTime, texting, e-mail, social media (Twitter, Facebook), taking pictures, taking videos, and some games. In truth, Android does these things just as well as Apple's iOS. Two things start to influence you: the amount of money you have invested in the platform (e.g. apps, games, and accessories), and your familiarity with the operating system. The average user isn't going to be spending a lot of time messing around with individual settings on the iPhone or an Android device. So when it comes to phones, buy what makes you happy. I truly believe that.
But for our family, the iPhone 6 represents yet another layer of refinement and reliability from a device that was already a part of our lives. We're pretty happy with our purchase and our move to T-Mobile, even though it took us a week longer to get our devices than originally planned. We will hold on to our devices for two years and plan to look forward to our next iPhone purchase–the iPhone 7 (2016).