I´ll keep this short and sweet.
PRO: Unbelievable zoom capabilities. I love astrophotography, and this baby can shoot the moon like no other camera. I can shoot individual craters now - a feat previously obtainable only with a telescope. Mars and Venus look like spherical objects, and the polar ice caps of Mars are visible. I can resolve the rings of Saturn with ease, the moons of Jupiter are child´s play, and even the Cassini division of Saturn´s rings is possible on a clear night. Terrestrial targets are equally easy. With a monopod, sitting in the nosebleed seats of a 75,00 seat stadium, I could fill a frame with a rock star´s face.
PRO: Good battery life. I´m able to shoot off an on all day when traveling on a single battery. I always have a spare charged and ready, but I only need it if I´m using the flash.
PRO: Excellent balance. Controls for zooming the lens are thoughtfully placed on the bottom half of the lens body, and the camera never wants to tip out of your hand, no matter what the lens is doing. And it moves back and forth about 6 inches!
PRO: Excellent fit and finish everywhere. Feels like a Nikon should.
CON: An unimpressive 16MP sensor. Also it isn´t full frame in size. There is much more detail in this tradeoff, primarily that a full frame sensor would necessitate a much larger lens to achieve the same maximum zoom, but there are 20-25MP CMOS sensors in this size range that would do the job nicely. At $1k, a larger sensor should have been put in. This sensor is the same one from the P900, why not upgrade it?
CON: Vulnerable lens surface. The front of the lens is right there, bulging out and ready to be scratched. Don´t even unbox this without a filter. 77mm please. Holy cow that is huge.
CON: RAW capability. Nikon seems to have gone to great effort to include this shooting mode. Which is a wasted in my humble opinion. There are lots of processing tricks yo can do on RAW images, but they take up a huge amount of additional space on your memory card, and take a long time to move from card to elsewhere. Anyone who wants RAW images is going to manipulate them on a computer, and it is child´s play to change from JPG or TIFF to RAW. I wish they had put the effort into the sensor.
PRO: EVF (electronic viewfinder). This baby is sharp, allows you to take photos in any lighting, and turn off the LCD screen too.
PRO: Rock solid image stabilization. In sunlight, you can easily shoot at 125x zoom without a tripod thanks to this. It´s an upgrade to the P900 for sure.
MEH: Heavy. Over 1.5 kilos! But hey, what do you expect? There´s a lot of camera here. The only thing they could do to lighten a device of this capability would be to include carbon fiber elements, which would have doubled the price.
OVERALL: Definitely the go to camera among all ´´bridge´´ cameras. The clear winner, even for the price, in the 30x zoom and greater segment. This will kill the P900 dead.

Biggest complain I read about this camera from early reviewers. it is big. I agree, this girl is rather voluptuous. But it is not larger than D500 if you F mount Nikkor 18-300 on it. Matter of fact P1000 is only 35g (roughly 1.5 oz) heavier. But then again, D500 with that lens has 10 times lesser reach.
I´m planning a big trip in a month and I am honestly debating should I take my new P1000 that will give me flexibility between macro and 3000mm or should I take much more advanced and faster D500 and juggle all the lenses I have in my bag. I think I will go with former. Will share pictures then.
P1000 has a greatest grip I´ve seen. If you just walking with your hand down, it balances well just on two fingers inside the grip. If you are taking a shot, you will need to use both hands but it feels great and fits perfectly, All controls are right where you want them.Stabilization on this camera is solid. If you have a good aim, you will get a good shot even with the lens fully extended to 3000 mm.
I agree with anyone who would say it is wrong to compare D500 to P1000 however, for the benefit of those that didn´t have a chance yet to take P1000 in their hands it is fair comparison.
Controls of P1000 are simple and intuitive especially for beginner. Zoom is spectacular beyond believe. It feels like the only limitation of the x125 zoom is the earth curvature and atmospheric effects especially on a hazy day.
This camera is nothing but fun to shoot with. It feels solid and the price is fair. RAW and 4K is great upgrade from older sister P900. EVF on P1000 is spectacular. Get the second Nikon branded battery. You will not regret having it in your bag.
Keep in mind you will not be able to sneak this “fat bottomed” camera to the concert or arena if no cameras allowed. But, you will be easily taking pictures from the roof of the building even if it is block or two away.
Get it and enjoy it.
PS. Just a wishful thinking. Now that P1000 out, I wish Nikon comes up with P950 or something that shoots RAW and 4K. or just Raw if 4K is not possible without major upgrade. It would totally worth it.