I'm extremely satisfied with my Canon Mark II's performance and durability, but I'm considering investing in another camera body. After a few months of indecisiveness, I'm still faced with a difficult choice between the Canon 5D and the just-announced Canon Mark III. Sifting through the mumbo-jumbo tech sheets, I've distilled the important (to me) differences to the following, with the advantage of each camera over the other in yellow, disadvantage in red, and neutral in regular. Again, these are my personal opinions but may serve you as well.
Canon 5D:
Cost: $2800
Buffers: 17 RAW frames
FOV crop: 1.0
Size: 6.0x4.4x3
Weight: 845gm with battery
Durability: magnesium-alloy body but not sealed
Frame Rate: 3 fps
AF points: 9TTL
Sensor Size: 36x24mm
Megapixels: 12.8
LCD size: 2.5" TFT
Canon Mark III:
Cost: $4500
Buffers: 30RAW frames
FOV: 1.3
Size: 6.1x6.2x3.2
Weight: 1335gm with battery
Durability: magnesium-alloy body and sealed
Frame Rate: 10 fps
AF points: 45TTL
Sensor Size: 28.7x18.7mm
Megapixels: 10.1
LCD size: 1.8" TFT but with Live View
Perhaps it's a simplistic comparison, but for me it boils down as to whether the high frame rate and the higher buffer rate of the Mark III is worth the price premium of $1700. Sure, the remainder of each camera's tech data is relevant...but what is really important to me are these two. I'm neither fussed about FOV crop difference, nor by the megapixel differential as I rarely, if ever, blow up my photographs to 18 x 24 and beyond. And yes, it would be nice to have the Mark III whose controls are similar to my Mark II, but is this and the higher buffer/fps rate worth the $1700?