I use an "old" Canon 1Ds camera—almost 2 years old and only 11 megapixels—and a "new" 1DsII, which is the current model. Surely, youd think, the latest and greatest must be best. But it just aint so. The 11-megapixel 1Ds model has some weaknesses, but I kind of like it more.
Ive taken good care of the old beast, or rather Canon has. Its had various repairs and adjustments including a new sensor and a new shutter. Now, after a years running-in period, it definitely meets or exceeds its published specs.
In fact, the old workhorse has just one real fault, namely noise. At over 320 ISO, mostly anything in the lower ranges of the histogram is riddled with specks. Still, because of the filmlike "look" I can get with the 1Ds, I am sticking with it for serious work. (My public thanks to the Canon engineers of the original 1Ds. You did a great job!)
Yes, the newer 16-megapixel model offers a much smoother high-ISO rendition, at least in theory. Greater dynamic range means fewer blown highlights. It also has inexhaustible battery life of more than a thousand captures; a clearer preview LCD that zooms and zooms; an SD card slot; and unflappable white balance detection (although my friend Andreas disagrees about this item, I think the white balance is really greatly improved). However, although the images are decently sharp, I find they somehow lack "bite".