60D + 24-70 f/2.8L II
It's a little heavy but lighter than carrying a FF and that monster of a lens around.
6D + 24-105L still beats it
Alright, I'll bite.
No, it does not! Unless you are talking about weight only (which I assume you checked somewhere) but I'm not interested in giving up my 24-70. Let me break down my argument in sections.
Sure, the 6D has better low light performance, better bokeh (given the _same_ lens) and a nicer viewfinder, just to name a few features. And these are differences that I can quote from having used the 6D next to the 60D, not from reviews. However, while we are at specs, the 6D has a lower max speed and a lower max flash sync speed than the 60D, and while the 1/250 of the 60D is not enough for a sunny day it does give you some more freedom than the 1/160 of the 6D (not a big deal, but something to mention).
Let's revisit the strengths of the 6D though (low light and bokeh). The combo you offer has a 4.0 lens, the combo I use has a 2.8 lens. This is a whole stop difference, which pretty much makes up for the 1.6 factor of the crop sensor in both light let in and bokeh. So while the 6D beats the 60D, the 6D+24-105 barely beats the 60D+24-70.
There is still the viewfinder of course, but whatever. I guess the 6D+24-105 is still better if you are doing low light landscapes with a closed down aperture for good DoF and high ISO to make up for the light, but who does that? I don't anyway and my post was about the equipment I carry.
- Return on investment:
I bought the 60D when I was on a much tighter budget, before the 6D came out, and long before I could afford the 6D anyway, since my walk-around lens was the Tamron 17-50/2.8. When the AF on that lens died, I decided to go the extra mile and buy a lens (24-70/2.8L II) that not only is far superior, but also enables me one day to switch to a FF body. At the time of purchase I spent $1800 for it (after rebates and whatnot). The combo you are suggesting is still about $700 higher (and that's if you buy gray market on ebay) and back then it was a good $1K higher.
- The limiting factor:
I view photography like sport car racing. If all you can drive is a Suburban, you don't need to move up from your Porsche to a Ferrari, you need to learn how to drive better. When you can fully control your Porsche and you miss some races because it can't deliver, then move up to the Ferrari. I guess I'm not the photographer you are, or don't do the type of photography you do (low light landscapes?) because I'm barely every limited by my camera. I've been limited by lack of sufficient control of external lights a lot, that's why my latest purchases have been speedlights, modifiers, remote triggers and lately a witstro 360. I've missed a lot of shots, and screwed up others, but I honestly can't think of a single shot that I missed because the 60D was not enough camera.
- The bottom line:
I shot those three over the holidays. Can you tell that they are done with a four year old underspeced camera?