Just thought i'd add my feelings as I have been using this phone for the past week and a half after trading my iPhone in and pre-ordering an S8.
I have had the Lumia 950 for ages but never used it as a phone.
All I will say, is that as a camera, it's phenomenal. As a phone, it's the biggest piece of junk I've ever used.
It is broken. On a broken OS that is packed with bugs, problems and clunkiness.
I do use some apps on it, Facebook, Instagram and Twitter.
Twitter is the only one that actually loads quickly and has no issues. The others take an absolute age, but 100% of the time they don't load at all. It takes 2 or 3 (sometimes more) presses of the app before it actually opens. And the time it takes for it to try and open is around 30 seconds. Only for it to not open. Every time.
Messages in Outlook do not download properly. Images in emails are set to auto download in settings, but they never do. I have to click to download them every single time.
WhatsApp's don't come through. My partner and I are both in a group and he has an iPhone 6. Messages go through to him in a group that I am also in - my Lumia doesn't get them. Well, sometimes it does, most of the time it doesn't. Not for a good 5-10 mins later anyway. It's great!!
Battery life is garbage. Doesn't last a day and I am hardly even touching the phone. It's not as if there is anything for me to do on the device. It's the worst battery I've had in a phone.
It also gets boiling hot when using. Any app that's open and it's roasting.
The keyboard is also not very clever. I can mis-type words like 'is' as 'os' and it won't correct it. It isn't intuitive at all. I will type something like 'all' as 'alk' and it won't correct that either.
It's just a bit stupid.
I am literally counting down the days when I can throw this back in the drawer and only ever have to use it when I need a fantastic camera. Because it wins in that department and that's it.
It's a great shame as the OS has a lot of potential. I truly wish the app support was there and Microsoft were bothering trying to make it useable as it really has a lot going for it, if it worked.
But as it is, this phone is garbage.