Upload & Sell: Off
I'm going to ramble a bit. People's reactions to my ramblings are appreciated.
I "grew up", photography-wise on a Nikon D90. It's served me well, but my problem with it was two-fold: it had focus issues with my particular 300mm f/4 lens which I intended to use for birding, and it was too big - a D90+wide zoom+ consumer telezoom + flash + consumer midrange zoom + support equipment took up half a carry on suitcase. (minor issues include that I'm not fond of its ISO 1600 performance, and really not fond of its ISO 3200 performance, as well as the fact that I think the D2x I got on a whim for a good price is a much better camera, except at ISO 400+.
All that said, I decided to get an Olympus EM-5 this year and went pretty far in with lenses - the basic consumer zoom kit (14-42 and 40-150) as well as the 12mm, 60mm, 14mm, and 25mm MF Nokton (expensive but awesome). This kit takes up, at most, 10% of a carry on and quite comfortably fits into a small backpack. For "walk around"/street photography (AF-S/MF+the 14, 60 or 25mm lens) or landscapes (the two most common types of photography I do) it really is far better, IMO, than the D90 due to size and equal, perhaps superior (with the lenses) performance. The built in image stabiization is also VERY useful for "walk around"/street photography.
This still leaves my other occasional photography form, bird/animals. I would like a new camera that has AF-tune. I was going to get a D7000, but then I saw that with Nikon's recent fire sale it was effectively $1000 over the used price of a D7000 ($700 on B&S, compared to $2000 with kit lens for the D600). I figured I'd give it a shot - if I needed DX I still had IMO acceptable DX megapixels, and not only would I get the additional dynamic range and high ISO performance but also a lot of my recent animal/bird photography has been at less than 300mm 35mm equivalent, so I think it's a win-win.
Long story short, I've been doing some basic tests with the D600, and I'm less than impressed.
First, its image quality, dynamic range, high ISO performance is of course amazing coming from my perspective. It's far better than the D90 and notably better than the EM-5 (perhaps two stops better than the EM-5 - I haven't done detailed tests). That being said, for much of my output, the EM-5 has been fine (I don't often print big, and if I do it's from a shot off the tripod, and if I really need more MP I can always stich). The one remaining virtue I could think of with the D600's high ISO performance, thinking from a landscape perspective, is that you get much more DR/much less noise if you use high ISOs to stop motion of, say, grass in poor lighting, and that astrophotography is easier.
For "walk around" purposes, the D600's stellar ISO 6400 is offset by the lack of IS for fast lenses (I don't have VR f/2.8 glass and would find the only one I can think of, the 70-200, way too big and expensive IMO for nonprofessional walkaround use). The D600 is notably bulkier than the EM-5 - my walk around kit can fit into 2-3 jacket pockets. The Nikon equivalents would be much bulkier. I much prefer the EM-5 as a walk around/street camera.
And the killer, for me, has been my recent tests with the D600 and AI/AI-S glass. I've found it much more difficult to work with MF glass on the D600 than the EM-5. Maybe it's just that I'm used to the EM-5, but still, the D600 does not have magnification in the viewfinder, nor does it have the back-door focus peaking of the EM-5. I thought I could manage with the dot system in the Nikon viewfinder, but I've found it a bit hard to use. For some odd reason I find the D600's LCD more cumbersome to use than the EM-5's.
So, the D600's nice, but IMO not nice enough to warrant the extra expenditure for FX glass I'd need to make. I think I would really have to sell everything else and shoot only Nikon FX to prevent the amount of money I've sunk into camera gear from bloating up. (even though lenses more than $1000 are not on my purchasing list).
Not is it, unfortunately, is it anywhere near as small and handy as the Em-5, which I was hoping it could be with some of the smaller, older lenses (24mm AI-S or AF-D, 135mm series E, 50mm f/1.8 AF-D and some others as a light walk around/lght landscape kit. Again, MF foibles and lack of VR is a killer here, more so than the D600's size which of course will never approach the EM-5)
I am probably going to send back the D600 (I'm still within the return period and I have not done more than very light testing with it, covered by my local store's return policy). For my birding, I will probably get a used D7000 - which has the added advantage of me not having to get rid of my DX glass, which I'm quite fond of performance-wise.
Anyway, again, any thoughts about my ramblings are appreciated.