I have bought 3 used, Canon 1D Professional bodies, for pennies on the dollar. The original 1Ds was a 8,000 dollar camera. I bought it for 220 dollars with a 100,000 shutter count, it's rated for 250,000. It works great. My 1D Mark III was a 6,000 dollar camera. I paid 550 for it with less than a 9,000, shutter count, it's rated for 300,000. Again it works great. Last but not least my 1Ds Mark III it went for 7,000 brand new, I got a deal and paid 600 for it, with a 90,000 shutter count, again it's rated for 300,000. If anything happened to anyone of these cameras, I would replace it with the same model.
I will bet American money, you couldn't tell a shot from one of my cameras, from the latest greatest model out there.
The money I saved from buying used bodies, went to buying used L glass. Again for less than half price.
It's like buying a car, I let someone else pay the sticker price.
It 's damn near impossible to stay, state of the art. Look at tv's, flat screen, to 4k, to OLED, to who knows what next. Although, I don't own one cell phones are the same.
I was a Union Pipefitter and I worked on a few Intel plants. I was talking to one of thier enginerr's one day and asked him about mirco chips and computers in general. He told me find one you like, one you can use, that feels right and stick with it till it dies.
Camera's are the same.
I finally got rid of my D80, and got a 3300. Of course none of the old lenses are compatible. I have 13x23 pictures all over my office that I took with my old D80. The quality is excellent, I get many complements. I have to question my wisdom of getting a new camera.
If a D3 does all that you need it to do, it's certainly worth considering....
However something hasn't been mentioned. With an older model like that I'd recommend emailing Nikon to see if they still service it. If anything is needed, can it still be fixed and will they have replacement parts, if needed? DSLRs are extremely complex devices and things wear out or break. If it's not possible to get repaired, you'd have an expensive paperweight!
Can't find a d700 at bh photo
Absolutely! I lusted after a D3, D3x AND D3s when they were introduced... didn't get one then but their capability isn't diminished just because the D810 and D850 (have both), D4 and D5 now exist. I'm not exactly gentle with my equipment 'cause I USE the stuff while doing things I like to do. I imagine I'll lose my D700 in a river or ocean swell or some other unfortunate event and when I do, that D3s will be on my radar...
I got a used D5300 as it was the only Nikon I could find with GPS which I needed for some of my clients.
I have had my D3 for about 10 years, and it's still in use. I also have an olympus D5markii, which is much lighter and easy to handle (the D3 is made for guys with HUGE hands), but sometimes there is the need for things like high iso or smooth files. It still works, been no trouble and I'm still on the batteries I bought when I got it, one Nikon and two Calumet. AS far as cropping goes, unless you want to crop something like a 4x6 out of a 20x24, no worries. I've taken it's tiny 12mp files up to 17x25, slightly cropped, and they look great. And I have worked doing printing and been a pro photographer shooting commercial and industrial, so I can be picky.
If you can tolerate the weight, go for it.
Also, I also had a D700 but it's results were soft. beware.