I would take a serious look at why I wanted to upgrade to a 1DX.
I own a 5DMKIII and a 5DMKII. If I owned a pair of 6D's I would not upgrade. You would not be able to distinguish my images shot with the 5DMKIII with the 6D. Now if you changed my lenses from my L lenses to cheaper lenses you could probably tell. I really think you need to look at what is driving your decision. If I were in your shoes I would get more L glass. more specifically I would get a 24Tilt shift for composite backgrounds. (I already own the 85 1.2L.. get that before a camera upgrade as well)
(See Joel Grimes video for use of the 24 tilt shift in portraiture) The reason I would get the 24TS lens is because I can create a 40MP image by splicing two images together. It works great for portraits in studio too with a little practice.
Although some really good natural light photographers aka Lisa Holloway use a 5DMKIII she could very well use a 6D and you couldn't tell the difference. The real difference between her and anyone else here is she knows how to get good natural light shots and she really knows how to process them. Most of the really good natural light photographers style and detail are brought about by their understanding and use of color grading.
Some photographers in a style similar to some of your stuff are:
Jake Olson (Primary Camera is a 5dMKIII) lens 85 1.2L
Lisa Holloway (Primary Camera is a 5DMKIII) lens 200 f2.
Jessica Drossin (Primary Camera is a 5DMKIII) Lens 85 1.2L
You can search for the above names on 500px.com to see the camera and lens they use on each shot.
The question you have to ask yourself is this.
If these great photographers that have tens of thousands of followers don't use a 1DX to create world class images. Then how is that camera going to help you?
A secondary reason not to get the 1DX is that it is nearing its end of life cycle. There will probably be a replacement for it in the near future. Chances are it will be a 30+ megapixel monster. Although theoretically the quality of the pixel is more important than the number of pixels,(Thats what canon attempted to sell everyone on this camera.) I elected not to buy this camera mainly because of the pixel count.
There are really two reasons to buy this camera.
1)You need the 12-14 FPS. Most photographers I know do quite well with 8FPS. I shoot portraits so I only need 1FPS.
2) You need the theoretical build quality. You're in the rain or hiking up mount Everest!
The bottom line is this. Lens before camera every time. A camera will(in most cases) produce no noticeable difference in the quality of your shot.... At least when the models are close like the 6D and the 5D and the 1D... The lens will make a much bigger difference. Your ability to correctly process your image after you take a well exposed, well composed, well lit image will make more difference than your camera or lens.
Other suggestions if you want to improve.
1) Buy a new 27 inch IMAC with lots of memory.
2) Buy a wacom tablet if you don't have one already.
Be sure and remap your wacom tablet to only use 1/4 of
the surface. You will never get good doing edits of your
images if you have to use full arm movements to do edits.
3) Buy yourself some other L glass.
4) Take every video course you can find.(Paid or free.)
a) Joel Grimes
b) Kelby subscription
c) Phlearn.com
d) Caras Ionut
e)
https://www.learnfromjoeyl.com (Excellent color
grading videos).
The bottom line equipment will only make you marginally better and the camera is the last thing you need to help you improve.
Regards,
Russ Elkins
I would take a serious look at why I wanted to up... (