The downer is that, personally, I wouldn't buy this phone. If I wanted the Z2's camera, coupled with its high-quality display and fast processor, I'd wait to buy it in a smaller version of the handset -- which hasn't been confirmed yet, but must surely be on the horizon given the level of interest in the Z1 Compact. If I wanted a phablet, I'd get a Galaxy Note 3 or hold out for a Note 4. And if I wanted a big, premium non-phablet, I'd probably go for the HTC One M8 -- it has a more enticing, more comfortable design, along with a nicer UI and better stock apps (especially in the camera department).
More objectively, though, I can see what Sony was trying to create with the Z2, and it has arguably succeeded in the areas that matter most. There'll be people out there who appreciate its gorgeous display, solid battery life and granite-like charm, and these attributes are inextricably linked to the phone's size. If you think that might be you, go ahead. This is a safe purchase, the best Sony phone that has ever been, and definitely among the top three Android phones currently on the market.