After using Lumia 820 for almost 2.5 years, Lumia 950 was perfect upgrade for me. I visited Microsoft Retail Store on day 1 and checked out the phone for real. Its indeed felt premium and super light and decided to pre-order it straight away.
Pros:
Super slim and light(comparing to previous Lumia devices)
Even though it has plastic body, it still feels premium.
Windows Hello IRIS scanner is just amazing. Works perfectly well in various lighting conditions.
With 3GB RAM and new processor 808 its does feel fast and peppy.
Camera. Speechless. 20MP, Carl Zeiss Pureview speaks for itself. With 4K video recording amazing.
Its has got best display around in the market. AMOLED with 556 dpi you can feel the difference.
WH-308 headphones are excellent. Bass is amazing.
USB type C charger works as they marketed. It indeed does charge your phone to 50% within 30 minutes. Full charges takes 60-80 mins.
With 3000mAh, battery is sufficient enough. I get around 20 hrs with wifi, 3g. And it still hasnt completed it charge discharge cycles.
Still to get the continnum dock but I am sure its going to be super awesome.
Windows Phone 10 does indeed feel refreshing even for Windows Phone 8.1 Users. There is noticeable improvement in terms of UI as well as performance.
Cons:
Windows Phone 10 OS is still not completed. So might notice unexpected reboots. My 950 reboots during IRIS scanning unlock but thats rare once in a day. If you are Windows fan, you wouldnt mind much and things are to improve as OS keeps on improving.
You might notice phone getting slight warm during charging or during high load application usage. But then these are the cons with slim phones.