I just did my own comparison of sample pictures over at dpReview (http://www.dpreview.com/previews/canon-eos-70d/10
; it is a nice tool they have there).
I compared the 70D with the D7100, the D600 and the 6D. I mostly looked at JPEG, but did also some RAW comparison. There was no surprise at low ISO, the pictures looked almost the same, hard to tell the difference, though the two FF's had a little advantage. At higher ISO the difference became bigger, and there where also some surprises. The winner to my eyes is the D6, it has the fewest noise and the most details, both in RAW and JPEG. Looking at the RAWs, the D600 is the second best, a little bit ahead of the 70D, and the D7100 falls behind. Switching to JPEG changes the result a little bit. The 70D catches up to the D600; the 70D shows less noise then the D600 in some areas, but the D600 stays a litle ahead in the details (no surprise, but I expected a much bigger difference; FF against APS-C). The D7100 marks the end again with JPEGs at high ISO.
So right now I'm pleased with what I have seen from the 70D. Of course, these were studio shots and real life is still a bit different. I'm also looking forward to the DXOMark results. Usually the Canons fare much worse there then in real life tests. But what is more important, good results in a synthetic test, or good pictures out in the field? It is like buying loudspeakers, the best test results with synthetic noise do not mean much, if the real music does not sound right.