Body & Design
The EOS 70D looks very much like the EOS 60D, although it's actually a little smaller. Body construction is mainly plastic, but in this case that's not much to worry about - it still feels nicely put together. All of the main shooting controls are in essentially the same places, but some of the secondary ones have been moved around or revamped. Overall there's not a lot of space left on the camera where more buttons could realistically have been placed.
Top of camera
The top of the 70D very closely resembles that of the EOS 60D. The buttons along the top of the LCD screen each serve a single purpose rather than doubling-up, giving direct access to autofocus and drive modes, metering and ISO (which is easily changed with the camera to your eye). The exposure mode dial has been simplified to group the various automated scene modes (portrait, landscape, sports etc) under a single position, and a pair of stereo microphones placed behind the pop-up flash housing replace the mono mic that was on the front of the 60D.
The small button between the shutter release and the front dial is a dedicated focus area expansion control. Pressing it allows you to expand the AF area from a single point to progressively larger groups of points - useful when tracking a moving subject.
The 70D's polycarbonate and aluminium construction doesn't quite have the reassuring solidity of the magnesium alloy build that many of its rivals offer - though it's hard to tell whether there's much real-world difference in terms of durability.
Canon's spec sheet for the EOS 70D says it has water and dust resistance 'equivalent to the EOS-1N' - Canon's professional 35mm SLR in the mid-1990s. It's debatable how much this information will mean to most buyers, but the implication is that it shouldn't be fazed by a splash of rain. The diagram below gives an idea of how the body is sealed (courtesy of Canon EU).
In your hand
The EOS 70D uses a fully-articulated touchscreen that's very similar to that used in the EOS 650D and EOS 700D. This means it's substantially improved on the one in the EOS 60D, as the air gap between the cover glass and the screen itself has been eliminated; this should improve visibility in bright light.
The screen can flip out and rotate to point directly downwards, upwards or even forwards for shooting self-portraits (in this position the camera handily mirrors the live view display). It can also be folded up with the screen facing inwards to the camera for added protection (or if you somehow prefer an old-fashioned film-camera experience).
The screen is also touch-sensitive, and as on Canon's recent entry-level models, absolutely every aspect of the camera's interface can be controlled by touch. In concert with the camera's Q button, it means a wide range of settings can be changed quickly and intuitively. This doesn't make so much difference while shooting with the optical viewfinder, when you'll probably want to use conventional 'hard' controls as far as possible. But it's genuinely useful in live view or when shooting from a tripod, allowing the focus point to be selected (and, if you like, the shutter to be released) simply by touching the screen.
The screen has a high-sensitivity setting which Canon says allows operation with (thin) gloves. Alternatively you can turn the touchscreen off altogether if you don't like it.
The EOS 70D uses a glass pentaprism viewfinder with 98% coverage and 0.95x magnification. This is an improvement on the 96% coverage offered by the 60D, and places it much closer to competitors like the Nikon D7100 and Pentax K-3, which both offer 100% coverage and slightly higher effective magnification. Of course it still can't match full frame cameras like the EOS 6D or the best electronic viewfinders, such as the Olympus OM-D E-M1, where the size of the viewfinder isn't limited by the size of the sensor (or, more accurately, the mirror in front of it).
The 70D's viewfinder also gains a switchable gridline overlay, along with the neat trick of being able to use the AF array indicators to display an electronic level in the viewfinder to help keep your horizons straight (both features lifted from the EOS 7D).