I like Mings preview:
http://blog.mingthein.com/2015/10/21/premiere-review-2015-leica-sl-601/
He puts the camera in context with the other alternatives.
Kristian Dowling, who like Jono, is working with Leica, had a good preview:
http://kristiandowling.com/blog/2015/10/20/the-leica-sl-type-601-professional-mirrorless-camera
Jono is also excellent:
http://www.l-camera-forum.com/leica-news/2015/10/leica-sl-test-jono/
What it took me a little while to realize is the bridge factor between the S system, which is now arguably the best DSLR sized option money can buy (with limits, e.g. sports and wildlife) and of course M. It appears the S adapter, which will support AF, is late, and will not appear till middle of next year.
R and Nikon updaters are available now.
The T mount is better than the E mount, because it's 50mm vs 46mm (torque) and should show less reflection and shading issues.
Meanwhile problematic issues of the Sony A7 system have been recently revealed in tests at Lensrentals:
http://www.lensrentals.com/blog/2015/10/sony-e-mount-lens-sharpness-bench-tests
Sony lenses are very hard to test on the optical bench, but these infinity issues have been resolved and results reveal huge copy variation in the native Zeiss lenses, and the need for 2mm of optical glass in the path to produce the best results (this may point to the coverglass issues)
So, while the Leica is bigger and much more money, it's the best legacy body for film lenses ever made by anyone. Pending additional adapters, but these are dumb and easy to make. We will see more, I think.
The Leica SL is headed to classic status, and one wishes Zeiss was paying attention. A Zeiss mirrorless FF, with good build and interface, friendly sensor and a price tag in the lower atmosphere would sell easily, I think. But maybe they already signed a non-compete clause with Sony
🙂