What's New and Dandy
The new viewfinder now provides 100 per cent coverage, unlike previous Canons in this range, and it uses a new polymer LCD network for the graphical overlay to display AF points, grids and other displays, so it's more flexible and feels more fluid. (It also just looks swankier, and again, more Nikon-like.) Your other viewfinder (when you're shooting video, anyway), the LCD screen, is a 3-inch, 920k dot display like the 5D Mark II and it's still excellent, with a wide viewing angle, nice colour and the right amount of crispness.
Sensor and Image Quality
I was expecting a noisefest, or at best, seriously noticeable noise reduction employed by the camera's software. It is clear that Canon's using incredibly sophisticated noise reduction algorithms with the dual Digic IV processors on board, though the effects are less drastic than I expected. It's most apparent, actually, when you directly compare photos taken with the D300s. Looking at photos taken with the 7D and D300s at 100 per cent crops, the D300s's images are noisier, but they also preserve more detail. For web-sized images, the 7D's images look better, with less noise and more smoothness.
You can get sense of Canon and Nikon's philosophical differences with the difference in their buttons for video: Canon makes a distinction between Live View and video mode, while Nikon is ready to start shooting video as soon you tap the live view button on the D300s. Creating video is a separate, dedicated event for Canon, in other words, and there is a semi-serious video camera that happens to be built into a DSLR. Nikon's D300s, on the other hand, is a DSLR that happens to shoot video.
With video, the 7D simply has the upper hand — video is very much a legitimised use of this camera, not a secondary one like the D300s. (As expected from a company with an entire wing dedicated to camcorders for pros and consumers.) Not only does it have full manual controls, I find that it's slightly easier to use the D300s while shooting video — not to mention the whole shooting in a real video codec at 1080p, yadda yadda. Three clips here: A melange of video above, and then by two videos, one from the 7D, one of the D300s, that mirror each other. Both were shot at ISO 6400, and you should be able to catch them at full res if you click over to Vimeo.
Build and Controls
Controls aren't radically different from other Canon DSLRs of this calibre — that is, it's what you'd mostly expect from a DSLR that sits in between the lower end 50D and the higher end 5D MK II, though it's a bit closer to the latter. While the menu system feels completely unchanged — leaving more advanced features, like the orientation autofocus a bit inscrutable — a few things are new on the outside: The power switch is up on the top left, under the mode dial; there's a dedicated button for switching to RAW/JPEG; a quick action button; and a new toggle switch for Live View and video, which you engage by pressing a start button in the centre.
You Already Know If You're Going to Buy This
The real question for Canon users who want something more than the lower end 50D is whether they go for the 7D, at $US1700, or full bore to full-frame with the $US2700 5D Mark II. The 7D has a 1.6x crop factor which is useful for sports, a better autofocusing system, shoots faster, is slightly more rugged, and is $US1000 cheaper. The 5D is full frame — which I suspect is the real consideration for folks — and takes slightly better photos at higher resolutions.
Obviously, if you're locked into Nikon, with thousands of dollars in lenses, you're not going to jump to Canon, or vice versa. But Canon's dedication to DSLR video is proving formidable in carving out a new kind of market that Nikon might have some trouble competing in, since they're a dedicated still-camera company, not a video company, too, like Canon. Really, both the D300s and 7D deliver for the money, though I think the 7D delivers more, since it's packed full of newer technology and for the people who want it, the video component is truly killer. Either way, it's proof that competition is good — it clearly wouldn't exist without the D300, and the D400 will be that much better because of it.
New 19-point autofocus and metering systems plus the new viewfinder rock
Excellent 1080p video with full manual controls
Not full-frame, which might put off some people
I'd like a secondary SD card slot, like the D300s
Noise reduction can get pretty aggressive at higher ISO speeds, obscuring detail