I apologize for the somewhat lengthy post in advance.
I just placed an order for the Canon 5DMarkIII and couldn't be happier. 
I started researching FF cameras back in August, once I read the specs, saw the early reviews, and saw some sample pictures of the Nikon D600, I was sold. Convinced my wife that spending $2,000+ on a camera was a necessity (it really wasn't), but she knew that it was on my mind and she didn't stand in the way. I had shot with Canons before and while it was comfortable to me, I had thought that I should try a change while I'm not so tied into one system. The mystique of the L lenses always appealed to me and the massive user base of Canons would make buying 2nd hand lenses much more affordable ($900-1,100 35L's vs. $1,300-1,600 Nikon 35 1.4's)
I asked the question "5DMarkII vs D600" on this forum a little while back and I was shocked to see that almost everyone recommended the D600. Maybe it was comparing a brand new camera to a 4 year old technology. Maybe it was the better DR. Even though I couldn't try out the D600 before I bought it, I confidentally ordered the D600, bought a 2nd hand Tamron 28-75 non-BIM, and placed an order for the 50 f/1.8g. Got the Tamron first, the D600 was on backorder on Amazon as was the 50 f/1.8. So I sat there with a lens that I couldn't mount, waiting. Finally got the in stock notification on the D600 from Amazon and was so giddy. Got the D600 and shock... it appeared to be opened already. Battery packaging was open, myshuttercount showed that my very first snapshot of a Coke can was actuation #3, etc. I emailed Amazon frustrated, they apologized, couldn't explain why I received a non 100% new. It would've been one thing for them to tell me it was opened before, but I bought it expecting a 100% new and it obviously wasn't.
Once I got over it and decided to keep it, mounted my Tamron on it and since I work until 6:30 most nights, by the time I get home I don't have time to go out and shoot. First dozen or so shots indoors were less than memorable. I'm by no means a professional but my expectations might've been unreasonably high. But I chalked it up to shooting indoors under possibly harsh and difficult lighting. First weekend rolled around, went up to a state park in NY, took the Tamron and while it was much better, pictures seemed less than sharp. Nowhere was I getting the type of IQ that I had seen in samples. Where as in some samples even in LL, I saw people doing 100% crops and it looking amazing, mine were horrible compared to it. I thought to myself 'that person probably processed the hell out of that image'. I asked a buddy of mine who also has the D600 to send me some of his unedited samples and there was a noticeable difference. So again I chalked it up to sample variation on the Tamron, that it was the non-BIM and possibly an older lens. Waited and waited, and finally got the 50 f/1.8. From everything that I've read about this lens, it is a bargain at $219, it is sharp, especially down at f/8 or so. Mounted it up, went to an apple picking farm in NJ, took a ton more pictures mixing up various f-stops, ISO combos, etc. Went home thinking it would be fine, then disappointed again. Even recovery in LR couldn't satisfy me. Even slight crops were full of noise, grain, you name it. It was at that point that I was fed up, maybe I did get a bad copy of the body, and I was determined to get a new one. Emailed Amazon and they said that since the body was out of stock, they could only issue me a refund and that I could reorder when it was back in stock.
Debating whether I should send it in to Nikon for them to take a look at, I vented my frustration to a buddy of mine who's makes his living as a wedding photographer. In the beginning he told me not to get caught up in the better DR of Nikon, not to get caught up on the specs, and advised me to get a Canon. Foolishly I went against his suggestion. So he lent me his Mark III over this past weekend to shoot with. Even when I picked it up the first time it just felt different. My first few shots weren't terrific, with the first 10 or so mostly being out of focus getting used to the AF system or blurry (realized I had IS off). But then the next 10 looked better, then the next 10 looked even better.
When I told my wife what I had thought, she said to me, yeah but that Canon has a 24-105L lens on it, you have a possibly 'soft' Tamron, you have a prime where you can compare varios focal ranges to, etc. She asked doesn't Nikon make a lens that compares to it. When I told her that the comparable Nikon is the 24-120 f/4VR and that it costs around $1,299 bringing my somewhat 'affordable' FF setup up to $3,398 and I showed her that the 5DMarkIII with 24-105 is now $3,798, she said 'isn't the much better camera that you talked to me for hours and hours about with the small price premium?' I happily agreed. So I spent the better part of last night boxing up the various goodies that I bought with the D600 (lens, filters, remotes, etc). Sent them off in the UPS store today!
Now awaiting my 5DMarkIII that will be delivered this Wed.
In addition, Amazon is including a few goodies that I'll be parting with to help offset the cost. A LowePro fastpack which I won't need, a memory card that will help save me $30 or so, and a $200 card for classes which I'll glady use. All in all, I'm happy to be back in the Canon family. Could I have made it work with a swapped body, more seasoning, and maybe more PP work? I have no doubt. Is the D600 an excellent camera? No doubt, I think that it is a great camera for the right person. But since I plan on shooting trips where I go on vacation with my wife, my upcoming baby, and mostly people, the Canon skin tones will be appreciated. And since the Canon JPEG engine is supposedly 'better' than the Nikon, shooting in RAW+JPEG will save me time when I'm up to my elbows in dirty diapers. I'll update this thread with pictures when I get the 5DMark III and have a chance to shoot it a little. I hope you guys will understand my momentary lapse and my drifting to the dark side.
Thanks everyone for letting me vent, letting me tell someone who might care (my wife stopped listening to me about a week ago, lol). And for anyone who's thinking of making the switch to the D600 or D800, don't be tempted so much by the specs on sheet, if you have a chance to shoot real world with them first, do yourself a favor and do that. It'll save you the frustration of having to box up multiple boxes to wait in line at the UPS store.



