Upload & Sell: Off
Now I get to decide the 20mm or the zoom.
If I were in the market for a smaller system to supplement my 6D, in the vein of 'take this and go shoot that' when out with family or friends, I'd jump on this, but I can't say whether I'd go for the prime or the zoom. I almost wish there was a kit with both for $150-200 more, and hell, throw in the Canon EF adapter for another $100, kit price; then I'd call it an investment.
Right now, I'd probably go for the zoom; there aren't any STM zooms for the 6D, I'm not buying any more EF-S stuff with my 60D now sold, and I have the 40/STM (which is the same basic thing). I'd miss out on the most compact function, but I'd have an STM zoom in the kit, and that's worth something.