Hi,
I am a bit late to this thread. All that I write hitherto is my opinion only and if you don't like it, just skip to the next post. And sorry for this long post.
I have D3x, D3s and D700 (IR), which were mentioned earlier in this thread. I also have (and regularly use) D2x and D1x. But let me begin a little bit further back.
The only DSLR cameras I have ever sold are D100 and D200. Instead I kept (and still use) D1x and D2x. There's a pattern, bear with me.
I have realized that for me the
camera is at least as important as the
digital in a
digital camera. Most published reviews are concentrating too much on the digital part, noise this and ISO that and DR everywhere, but mention only in passing the camera abilities.
Let's get back to the topic. For example, a D700 is 95% the same thing as a D3, but to get the vertical controls and frame speed up one needs the grip, EN-EL4a battery and a charger which makes the D700 cost the same. Furthermore the end result is both bigger and heavier than a D3. I prefer the smaller D3 body which still has better controls and more functionality. As a sidenote, I didn't want to sell the D700 in the declining market and instead had it converted to infrared.
The image quality of both D1x and D2x above base ISO is easily surpassed by D200 and D300, but the handling of the full-size bodies is better. I actually shot at a wedding today with D1x, D3s and D3x. Yes, D1x, no typo there (my D2x is in the shop for hot shoe replacement). Using those cameras side by side was easy, I could switch from one to the other with my eyes closed and let my hands do the work.
The point in this rant is that one needs to assess the whole package. I shoot a lot of verticals and really need the vertical grip and controls, but not the size and weight of removable grips. D800 beats my old D3x in image quality by a comfortable margin and I think the new(ish) D600 delivers images very close to D3x, maybe even better?
If one is after the D3 image quality alone, then a D700 can do it and D600 does better. Heck, I believe D7100 does better. If on the other hand one needs certain camera functions and controls and the vertical grip, even a D1x can be a very capable camera.
I am happy with my gear, really, and use all of them. If either of my D2x or D3x fails, I will have them repaired regardless of cost. My next camera will be a D4x or a D5 or whatever there will be. D4 does not offer enough between my D3s and D3x, so I'll pass.
Are pics allowed in this thread? I will remove it if I broke the rules.
This is a recent candid of my daughter in the playground, while she was waiting for her turn looking frustrated. I shot this backlit grab with a D1x and had to push process her face about two stops. I am still happy with the end result of a jurassic high-noise low-dynamic-range slow obsolete klunker.
For example a light and compact D3000 would deliver much higher image quality, but wouldn't offer the controls I needed. I could change the focusing mode from single-servo to continuous-servo and AF-pattern from single-area to dynamic-area without ever taking my eye off the viewfinder. That's what makes all the difference to me. Being able to shoot higher IQ but missing the shot just doesn't cut it.
So, remember to carefully review the camera too.