Thanks for starting this thread and doing so in a way which doesn't start a flame war. It's so nice to read constructive comments.
I recently bought a Lumia 930 and love it, though I miss Glance. However, it cost ?160 less to buy than my old Lumia 920 and I got ?100's worth of free accessories from Microsoft. With the money I saved over an iPhone 6, I could buy myself a Lenovo Miix 2 or Dell Venue Pro 8. What this shows is how much better value a Windows Phone is over an iPhone, because spec wise, a 930 is comparable and has features which the iPhone lacks - like dedicated camera button, physical OIS and wireless charging - that are well worth having. Build quality is similar as well, so I'm beginning to wonder whether the much vaunted app gap is worth initial cost difference.
I have a colleague who has an iPhone 6 and it is very much what I expected; not entirely a good thing. Build quality is good, but so it damn well should be and the look on my friend's face when I made to bend it was priceless.
To have an iPhone is to live in fear of breaking it, because of the replacement cost. It requires a case or cover of some sort, so styling is irrelevant and thinness a necessity, not an aesthetic choice. This iPhone now sports a screen protector (which I doubt it needs) and a clear plastic case which has already trapped some dirt. My point here is that with a Lumia you can have high specs and cool styling without having to curate it.
There is another hardware thing the 930 has over the iPhone, it's
battery life. My colleague and I have very similar usage patterns, though I tend to use Bluetooth more and he watches a couple more videos a day than I do. He is finding the battery adequate, but it is a worry to him - he would do more if he could. My battery life is all I need, I'm never afraid of playing a game or watching a video and not being left with too little power for the rest of the day. What's more, because of wireless charging, the device is never tied down. Recharging the device is an entirely natural action and there is no bother picking it up if you get a call or want to look something up. The advantage of this was recently bought home to me by another colleague, who uses a Galaxy S4. He bought a spare battery and it came with a charging case, so he could keep a battery on charge all the time. This is a really cool solution, except he has to switch off his device every time he needs to swap batteries. Given that one of my free accessories was a
DC-50 wireless charging plate and power problems are history. PS: The Lumia 930 comes with a DT-601 charging plate, but I don't like it because it's hard to find the sweet spot, the DT-900 is better.
Those are some of the hardware features which keep me on Windows Phone and I'm confident that the 930 is a worthy successor to a 920 or 925. That remains true without the free accessories, by the way.
Software wise, both Windows Phone and Cortana are not just quantitative, but qualitative advances over iOS and Android. This is because when Apple made a touch operating system, they had a failure of imagination; they adapted the desktop for touch. Microsoft on the other hand, had to implement a whole new paradigm and this means Windows Phone is proactive, not merely reactive.
Just put your 925 down on the table and it will already be telling you the time and showing notifications, while the iPhone will be a blank screen. Double tap to wake and you now know the day and weather conditions - or your next appointment, depending on how you have it set up. The next point goes to the iPhone of course, because turning on the device and logging in are combined, but once you've entered your pin, Windows Phone regains the initiative by presenting the next five day's weather, a news headline and your next appointment - while iOS only has static icons with little numbers showing the number of unread messages, etc. Next to Windows Phone, iOS is dull and uninformative. The same is true of Cortana over Siri and Microsoft have only just started in that direction.
My final reason to stay with Windows Phone is the future. It's difficult to see how Apple can do anything but refine what they already have in iOS, whereas we already know Windows 10 is coming and that even if you stay with your 925, you will get it. Already qualitatively ahead W10 will be another qualitative step forward with Microsoft being the first to offer coherent access to your digital life independent of the device you use to access it with. I wouldn't be surprised to see full multitasking, the ability to run two apps on the screen using the snap feature and embedded controls on live tiles, so you can control playback of music or do simple calculations
without even leaving the start screen.
I really think Microsoft have the best vision for the future, that Apple have lost the initiative and Google never had a clue in the first place.
If you decide to get the iPhone, good luck to you, I hope it serves you well. But I'm staying here where I'm comfortable and where I think there is most scope for the future.