I'm upgrading from an LG G2. The phone still runs great, but I have cracked the screen slightly and was already looking for something new. I also can't wait to have a Nexus again after my Nexus 4's digitizer stopped responding.
Furthermore, the Nexus 6P seems to tick all the right boxes for me. It has a very large battery, dual front facing speakers, a large and beautiful display, and a very premium aluminum uni-body, which I've loved ever since the HTC One (M7) was first unveiled. The fingerprint scanner and the USB type-C port are also things I'm really looking forward to, as they improve the ease of use and security, whilst also making the phone more future-resistant.
Finally, their's the price. Staring at £440 (at Carphone Warehouse) or £450 (at the Google Store) in the UK, the phone cannot be described as 'cheap'. However, compared to other flagships of similar specs, the 6P is definitely the best value-for-money. Yes, the Moto X Style is slightly cheaper, but in my opinion, not as good. The aluminium uni-body, camera (potentially), fingerprint scanner, and the fast updates for at least 2 years, are worth more than the £40 you will save with the Moto.
The only thing that has me worrying about the 6P is the large bezels up front. I get that they are slightly bigger due to the front facing speakers(which I love), but they really make the phone look much bigger. Coming from a G2, with very thin bezels and a very high screen-to-body ratio, it will take some getting used to. Having said that, it still has a bigger screen-to-body ratio than the iPhone 6+ & 6S+ and the HTC One M9, which should be fine.
Overall, I cannot wait to use this amazing device, and to be a Nexus owner once again.