The best image quality, particularly on full frame, is the 16-35/4L. It's also reasonably compact and the only one of the three with IS.

6D can shoot action... but it's limited to the center AF point only. That's the only dual axis-type point it's got. It's also the best one for really low light, allowing the camera to focus in -3EV light. (1DX, 5DIII, 7DII & 80D can, too... using limited AF points. But most other Canon are -1EV, at best.)

All the 6D's other points are slower single-axis type and not up to either low light or moving targets. However they're just fine for a lot of things. The 6D will be excellent for landscape and portrait work.

I have been pining to get a decent Full Frame camera to supplement my Canon 7D MII crop sensor and, after months of browsing Amazon, B&H, Adorama, EBay, etc., I finally pulled the trigger.

I had been considering buying either a used 6D or used 5D Mark II for non-action stuff like landscapes and portraits, but today I saw that Canon had the 6D refurbished for $1099, $260 off the regular refurb price - the best price I've seen so far for essentially a new 6D. I bought two speedlites from their refurb store and I could not tell they were not new! I have heard that they go through their refurbished items them probably more extensively than the QC new items get off the line. Plus it comes with a warranty (albeit not as long as a new Canon).

I admit this was a bit of an impulse and I went back and forth all day - I actually had it in my cart 2 or 3 times, then got cold feet thinking I'd be better off buying a used FF but finally, late tonight, I decided to just pull the trigger and give myself a slightly early Birthday present (BDay is early August). This was one of Canon's red-price specials where they line out the regular refurb price and put it on sale and I know that those deals are fleeting, so I figured if I didn't jump it would be sold out and I'd be kicking myself.

They also have the 5D Mark III refurbished on sale, but even at the sale price, it was a full $1000 more than the 6D. From everything I've read, the few things you give up with the 6D vs 5DIII (only one card slot vs 2, slightly simpler AF, slower frame rate) are offset by some things the 6D has that the 5DIII doesn't, like GPS and WiFi. Since I'll be using it mostly for things like Portraits and Landscapes, I felt like the 6D was a good option to get my feet wet in the Full Frame world.

Now for the hard part - waiting until Brown arrives!

The best image quality, particularly on full frame, is the 16-35/4L. It's also reasonably compact and the only one of the three with IS.

6D can shoot action... but it's limited to the center AF point only. That's the only dual axis-type point it's got. It's also the best one for really low light, allowing the camera to focus in -3EV light. (1DX, 5DIII, 7DII & 80D can, too... using limited AF points. But most other Canon are -1EV, at best.)

All the 6D's other points are slower single-axis type and not up to either low light or moving targets. However they're just fine for a lot of things. The 6D will be excellent for landscape and portrait work.