I got my iPhone 6 Plus yesterday. I've wanted an iPhone with a larger screen for a while. I used the iPad Mini as my smartphone for most of 2013 before moving to the 5" Nexus 5. I got fed up with Android after 6 months and have been using an iPhone 5 for the past few months. I found the Nexus 5 very manageable and figured an extra 0.5" of screen would be no problem. The 5.5" iPhone 6 Plus feels a lot larger and heavier though. The Nexus 5 is actually about the same weight and size as the 4.7" iPhone 6, though the iPhone is a few mm thinner. Holding and typing
The 6 Plus is great when using it with two hands to read, browse the web, play games, etc. As expected, doing anything anything with one hand other than scrolling is all but impossible for me, a tradeoff I am willing to make. I thought thumb typing with two hands would be a big improvement due to the larger keys, but it's actually somewhat frustrating. In portrait mode the extra weight and height of the phone makes it feel top heavy, like it could slip out of my hands easily. In landscape mode a few columns of keys have been added on either side of the keyboard, so the letter keys don't get any larger and they are located in the middle of the screen where it's a bit of a stretch to reach. I tried out a 3rd party keyboard that has slightly larger keys and it's actually nicer to type on than the stock keyboard.
What is all that screen good for?
The big screen is really nice for watching video, playing games, and reading. I primarily use my tablets for reading, watching short videos, and web browsing, and I was hoping the 6 Plus could pull double-duty and replace my iPad Mini. However, a lot of apps and websites (mine included) simply scale up to show the same amount of content they would on a regular iPhone 6 or even an iPhone 5. This doesn't really put that extra screen real estate to use, at least not yet.
Many of Apple's apps have a split-pane view. For example, in Messages or Mail you'll see a pane on the left with recent message threads. The home screen also works in landscape mode. These are nice touches, but it's frustrating when opening something that doesn't support landscape mode, such as the Phone or Podcast apps. I wonder if split pane views would work on the regular 6, I'm willing to bet some third party apps will try. There aren't any other software modes or special apps that take advantage of the additional space (yet).
6 or 6 Plus?
I'm guessing that many of the software issues I've mentioned will be fixed, either by Apple or with 3rd-party apps. There is also the possibility those enhancements come to the smaller 6 in time. I still like the idea of a really big iPhone, but only if it does more than its smaller counterpart. Right now I think I’d be happier with the 4.7” iPhone 6. In most places I'd see the same amount of content, and it feels better in the hand to me. Maybe I'd start to miss my iPad Mini though. I'd be giving up some battery life, but gaining a hundred dollars. I'm going to give it a few more days, but I'm leaning towards trading it in for the regular 6.