Preface: I've been using Canon since the 10D and have had every camera in the series except the 60D and now have the 70D (sold my 7D). I've spent the last couple of hours processing some 70D pics and looking at some of the work I've done with the 40D, 50D and 7D.
I can honestly say, IMO, that the IQ difference amongst the cameras it's evolutionary/incremental at best. I tend to shoot landscape and architecture on a tripod and from an interface ease of use perspective, the 70D is by far the best of the series for my particular use cases. Live view shooting is simply fabulous and I enjoy it as a walk around camera.
WRT the review and as a 70D owner, I was thrilled to see the 70D get a Gold Award but I find it a little hard to swallow from an IQ perspective due to the incremental changes. Love the better Hi ISO but in no way this is a revolutionary IQ camera even relative to the 40D.Anyway, for me, it suits my style. For better IQ, it's time for a 5D3.