Canon just announced their latest DSLR: the Rebel T4i. This camera has 18 megapixels on an APS-C sized sensor.
The T4i is very similar to the T3i, but with new software, a new processor, slightly different auto-focus, a touch screen, and improved video capabilities. The major improvements are in video, which include continuous auto-focus, stereo microphones and the availability of silent lenses.
The T4i retails for $950 with a lens.
The D3200 is Nikon's latest DSLR. This camera has 24 megapixels on an APS-C sized sensor.
The D3200 is Nikon's replacement for the D3100, but it's a complete redesign. It retails for $700 with a lens.
So which is better? Which should you buy?
DxOMark ranks the D3200 as the 10th best digital camera in image quality, right up there with some great full-frame DSLRs and not far behind some large-format cameras. While they have not tested the T4i, they have tested the identical sensor found in the T3i, and it ranks 68th best (hard to call it "best") in image quality. While the T4i might score higher with the improved software, it won't likely score much higher.
Even so, either camera is perfectly capable of capturing great images in the hands of a skilled photographer.Your camera isn't nearly as important as you think it is.
With that said, the D3200 is both significantly better and cheaper than the T4i, so the choice is a no-brainer. The one caveat is if you plan to use the camera primarily for video: the T4i has some alluring features that you may find worth the higher cost and sacrificed image quality.