I did the switch, from T3i to Nex-6.
At first, there was a bit of adjustment, but I learned to use what I had to achieve my goals.
For me, the biggest thing was the ability to get similar quality photos in a camera package that is smaller then some of my old Canon _lenses_. Even if I had to sacrifice some features (AF speed and fast zooms; although AF speed has improved since I made the switch). The longer I use this setup, the more I find myself reaching for the smallest lens as opposed to the best IQ one. E.g. I have 18-105/4 which is a very good lens but about the size of a 17-50 for Canon, but I more often just use the 18-55 kit because it's so much smaller and the resulting difference in IQ is for most part negligible. I can fit my camera, a zoom lens (either 18-55 or 18-105), a 12mm lens (16/2.8+UWA adapter, still tiny even with adapter mounted), throw in a fast prime (50/1.8 usually), three spare batteries and a charger, and it all fits in a 11" x 11" 2-compartment messenger bag I used to carry my iPad around, with room to spare. So I have a 12-105 mm coverage, all in a bag I wouldn't be able to fit my T3i with 17-50 attached.
If you get into A7, even if you keep your Canon lenses, you can still get a FE lens(es) and convert from a large to a small setup with a simple lens change. Not possible with Canon bodies, even SL1 is too thick.
What I still miss are Canon colors - I find them to be the best for Caucasian skin, Sony raw files require more fiddling with WB to get pink skin colors. I used to miss the fast f2.8 zooms but I can live without them.
