Customer Rating: 
Summary: It's really really great, but not quite quite perfect.
Comment: Look, this is an outstanding camera. It really is. I think others have probably already expounded on its greatness better than I can so I will keep this review (reasonably) short.
Here are the three things that jump out at me, and I will be comparing this camera to the Canon 5D (full frame) which I used previously to this.
Sharpness: Good god this camera is sharp. To me it is noticeably better than the 5D in terms of definition, detail and sharpness. I have gone back and pulled out similar pictures taken with the 5D (5D with L series lenses) and they are not as sharp. I am a sharpness whore and a pixel peeper so trust me on this. It's amazingly sharp.
Auto Exposure: very good; but not blow me away great. It will take some getting used to and I think perhaps I will have to fine tune it more than I thought I would have to. I'm really just nitpicking here; it's not a big deal and it's not bad; again just not blow me away great right out of the box.
Low-light performance: I'm sorry, but the 3-year old 5D has it beat big time here. I know it's unfair in a certain sense since the 5D is full frame, but as I said I think this camera has it beat in sharpness which is not supposed to happen when comparing a cropped sensor to a full frame. The fact that it wins sharpness is huge. Unfortunately, the low-light performance is nothing to write home about here. It is certainly better than the D200/D80/D70/D60/D50 (all previous Nikons I have used) but noticeably worse than the 5D. I'm not sure if Nikon was marketing this camera as a good low-light performer like the D3 and the D700 (I don't pay much attention to the marketing stuff) so this might not be a detraction but I just thought I would mention it since people care about low-light performance more and more these days. Of course also I am speaking from the standpoint of someone who has to market/sell most of my pictures. I rarely take pictures for fun unfortunately. I am quite sure that for anyone not using the low-light feature for professional work intending to be sold, it will be more than fine. Frankly it will even be fine for some professional work at ISO 400-800 but nowhere near the level of competence of the D700/D3.
Bottom line, in most situations this camera is superior to the 5D which really is saying a lot since the price is half and the sensor is cropped. At the end of the day, however, if low-light performance is key to you then I would recommend the Nikon FF D700/D3 or the Canon full frame offerings such as the 5D.
I haven't used the video feature yet (and probably won't for a while since I bought this to take pictures) so I don't have anything to report there.
Ergonomics are great and battery life is awesome.
Overall after shooting a few thousand pictures with it my rating would be 92/100. Again please take any of my seemingly negative opinions as what they are--my attempt to be thorough because I know some people want to know the finer points of some of these issues. I do not have a negative opinion of this awesome camera by any means.
Customer Rating: Summary: A Camera for Soccer Mom and Taekwondo Dad
Comment: I think most of us buying D90 would be someone like me. Goto review website for technical review and skip the rest. Read mine if you use it like I do. Here you go. Enjoy!
I have a D50 and just bot a D90. I shoot primary my daughters' school events usually indoor in a gym or threater. I have some of Nikon better F2.8 glasses. With indoor lighting and action such as TKD. The results are sometimes less than satisfactory. When using flash, the subject is well lit but the background would be dim. (you could solve this placing multiple flashes in the GYM like the professionals) when not using flash, you get hand shakes and motion blur. I shot my daughter's TKD blackbelt test yesterday, the D90 blew me away. Here is what it does, on Sport mode with Flash, it selected ISO 1100, F4 and 1/60. subject is well lit, the back kick is frozen to show the form, the foreground and background of the GYM were well lit. The white balance is perfect. I could not have done a matter job myself in manual mode! At the same sport mode, D50 chose ISO 500, F5.6 and 1/60. The subject is well lit, the gym background faded into darkness. When not using flash, D50 just can't get the white balance correct no matter how i set it. D90 white balance was perfect.
The D90 giant colorful LCD really tells instantlly if I have got the shot. I would buy D90 again just for catching the highlights of my daughter's belt test.
D90 is actually the same size of D50. D50 felt more comfortable in my hands initially, but after 3 hrs, the D90 felt just better. It could be a weight issue. I don't know why.
So bye bye to my wonderful D50. Hello to D90.
Further edit:
After a few weeks, it is clear Active D lighting works wonder. It lights up details which are lost when using a Canon 5D without post-processing. I would buy it again just for that. The custom FUNC is also a welcome addition. I set it to open my favorite menus making everything fast. I used to use flash whenever indoor. You don't need to do that in most cases anymore. I shot Halloween at Hollywood Blvd, pictures have good color and exposure using available light. It was unimageable with the D50.
Good shooting!
