Canon 7D vs Canon T2i (550D)

Canon 7D and Canon T2i has similar image sensor which is 18 MP, and produce almost identical image / video quality. So, why many people still opt to get 7D? It has to do with the processor, AF technology and built quality. With dual processors, 7D can process image data a lot faster. 7D can shoot 8 frames per second while T2i only 3.7 frames per second. 7D also has higher auto focus performance and it has magnesium alloy body instead of rugged plastic.

Here is Canon EOS 7D main advantages over T2i

Magnesium alloy body vs plastic
8 frames per second vs 3.7 fps
High performance and customizable 19 AF points vs 9 points
Top LCD screen
Larger and brighter viewfinder
Wireless flash commander
Round dial and better user interface

and Canon T2i also has advantages over 7D

$700 cheaper (around 45% cheaper)
Smaller and lighter (300 g / 37.5% ) in size
3:2 ratio full coverage LCD screen
Auto ISO up to 6400 instead of 3200
Dedicated exposure compensation button

Recommendation

I recommend Canon 7D for photographers who demand high performance camera to capture action photography, candids, wildlife, and Canon T2i / 550D for photographers who like small/lighter DSLR for travel, studio, still life, or anything that does not require high speed camera.

Table comparison

	Canon EOS 7D	Canon EOS T2i / 550D
Image	18 MP / APS-C Sensor	18 MP / APS-C Sensor
Processor	Dual DIGIC IV	DIGIC IV
LCD	3 inch 910k resolution	3 inch, 3:2 ratio, 1 million resolution
Dimension/weight	148 x 111 x 74 mm (5.8 x 4.3 x 2.8 in) / 820 g	129 x 98 x 75 mm (5.1 x 3.9 x 2.9 in) / 530 g
Viewfinder	Pentaprism, 100% coverage, 1.0 magnification	Pentamirror, 95% coverage, .87 magnification
Auto Focus	19 cross type AF points, customizable zone system	9 point system
ISO	up to 12800, auto ISO range up to 3200	up to 12800, auto ISO range up to 6400
Movie recording	1920 x 1080 (29.97, 25, 23.976 fps) 1280 x 720 (59.94, 50 fps) 640 x 480 (59.94, 50 fps) MOV (Video: H.264, Sound: Linear PCM)	1920 x 1080 (1080P, 16:9) @ 30/25/24 fps 1280 x 720 (720P, 16:9) @ 60/50 fps 640 x 480 (4:3) @ 60/50 fps Quicktime MOV format (H.264 video,linear PCM audio)
Continuous shooting	8 frames per second	3.7 frames per second
Handling/Control	Top LCD, round dial, joystick, virtual horizon, lens focus micro adjustment	Exposure compensation button, four way buttons
Body material	Magnesium Alloy	Rugged plastic
Price	$1550	$850