Re new Canon 24-70mm: here is a quote from LensRentals blog after they tested it:
"This is short, sweet, and simple. The resolution absolutely, positively kicks butt and takes names. It is way better than the lens it replaces. Itís better at 70mm than the best Canon zoom I know of, the 70-200 f/2.8 IS II. Itís even better at 24mm than the sharpest 24mm prime we have, the Canon 24 TS-E. In the center, in the corners, it doesnít care. We only had 5 copies to test, but they were all very similar with little copy-to-copy variation."
Things are certainly getting mighty interesting if Nikon can make a 14-24mm fast zoom which beats most primes, and Canon can make a 24-70mm which also beats great primes and longer zooms. What is coming when somebody really puts all the modern design power behind a fast prime design effort? (well, Fujinon XF 35mm is a good example, but it is not FF).