I have done two four-mile runs in my shoes and so far so good.

(but actually he really isn't because my orthotics cover him up)
Monday I ran with my orthotics under Sir Newton and Wednesday I ran with them on top, which is how I should be doing it, but of course the orthotics rubbed a blister on my arch on Wednesday. I did both runs without socks and aside from the orthotic/arch issue on Wednesday I am still very impressed. I have not run on the park trail yet though - I'd probably need socks for that as the toe box is mesh and little rocks and dirt can easily get in there.
So far I do not have any residual soreness in my achilles, feet, or calves which is sometimes common during the breakin period, or could also indicate the shoes are not for me.

(See, Sir Isaac Newton is looking at me every time I put my shoes on)
(but actually he really isn't because my orthotics cover him up)
Comments
I'd guess that you not having residual soreness means that your body is already used to running on the fore/mid foot. That's awesome! Until I got used to it it was a bit sore. Haha. But I'd definitely say that they've improved my form... now to work on my speed! haha. :-)
Happy training!