I've been a Canon shooter since high school and my class is having our 40th reunion next weekend. My current Canon bodies are the 1Ds Mark III and 5D Mark III. I have a variety of Canon "L" glass and Zeiss primes. Love them all!
Most of my photography is either street, family or travel. I purchased the Fuji X-E1 a month ago along with the Fuji 18-55 and 55-200 zooms and the Zeiss 12mm and 32mm Touit prime lenses. After playing with these and pixel peeping using Lightroom 5.2 for a few weeks, I'm really impressed with the image quality. The lenses are all tack sharp and the Fuji X-trans sensor is remarkable for color, sharpness and low-noise. I'm in love with the compact size and low weight. I can fit the whole system into a small Tenba Mini Messenger bag and carry it all day long. In contrast, my Canon 5D with 24-105 L lens and 16-35 zoom in a backpack weighs a lot more.
Now, I just listed my Canon 1Ds Mark III for sale in this forum. I will keep the 5D Mark III because the focusing is awesomely fast for action photography. I plan to only take my Fuji X-E1 on my next vacation to Spain next summer. I also just ordered the awesome Fuji X100S as the travel back up camera and to use for very discreet street photography as it is very small and virtually silent.
I did check out the other mirrorless systems, but settled on Fuji X because of the overwhelming amount of good press they are receiving from pros and advanced amateurs for a lighter, more compact solution with no sacrifices in image quality than lugging around FF DSLRs.
Check out this website for firsthand stories: http://fujifilm-x.com/photographers/en/