Just wanted to say thank you too everyone that helped make my decision.. I purchased the D600 and in just one night of playing with it, this camera is amazing even with just the kit lens! Now all I need to do is start a wish list for some good glass and take advantage of all the potential this baby has, hopefully this will take my photography to the next level.. Thank you guys hope you all have a great Sunday!!
One other thing, are you sure you need a full frame sensor? It used to be a foregone conclusion that everybody would be moving to a full frame sensor at some point, but unless you're really interested in wide angle lenses, I'm not personally sure that the file size and cost really make much sense. But, I've got a long lens addiction that might be talking for me.
It's definitely a valid choice, but the price difference between the two would be sufficient to get some really good glass. Which is why I asked, unless somebody really needs wide angle lenses, going with a crop sensor and getting some good glass is often a better choice.
If the manufacturers opt to stop selling the entry level dSLRs, this is going to be the biggest problem. IMHO, it's often better to buy a Rebel and an L than a 60D or 7D and just a very good lens. Obviously, dependent upon the specifics. Just because of how long a lens will last.
If you like(d) your Nikon, just stick with it. As the others have said you'll be use to it. That's probably the major reason I'm staying with canon - I'm use to it and my first camera was a canon. It's done me well Both are great brands and it's easy to upgrade glass on both of them it seems it just really comes down to brand preference, and you get more megapixels with the Nikon D600, and it has a little bit of a quicker burst rate.
I don't think you'll be at all disappointed by either one, I'd lean towards Nikon since that's the interface you're used to. However I'd be more worried about the glass, keep in mind to keep up with either camera you'll need some delicious full frame goodness to put on the front Best of luck deciding, both cameras look like fun toys
What limitations does your D90 have that you are looking to overcome?
What sort of shooting do you like to do best? What sort of lenses do you shoot with now and what are your dream lenses?
Both of these cameras are very high quality and for almost all photographers they will produce very similar results. When compared in a lab the D600 seems to edge ahead in reviews but I wouldn't put too much weight into that.
I am pretty invested in Nikon and that is where I will stay but if every piece of gear I own was lost and I had to start from scratch I would be really strongly considering Canon for a couple of reasons. (I also might take a look at Sony) First being that Canon production is simply better because Canon is a MUCH larger company. Nikon seems to have shortages and waiting lists for a long time while Canon gets new products to customers pretty fast. This seems minor but I was not a happy camper when my main body died last spring and I had to sit on a waiting list for 6 MONTHS waiting for a D800. The other major one is nikon's lack of super fast F1.2 primes in the 50mm and 85mm focal lengths.
That said Nikon still makes FANTASTIC cameras and lenses and many of their offerings exceed Canon, just like many of Canon's offerings exceed Nikon. When comparing the two I would focus on what one side offers that the other simply doesn't rather than quality between two similar bodies. Here are a few examples:
Things Nikon Offers Which Canon Does Not: A Camera with a 25+mp sensor A Camera with now low pass filter Lenses with "Defocus Control"
Things Canon Offers Which Nikon Does Not: 50mm and 85mm F1.2 primes A camera with 11 FPS shooting (1DX) Better supply
Obviously any of this can change at any time but it is a good point of reference. It also showcases what cutting edge technologies each respective company is investing in which can help predict what their goals are moving forward.