I took this bra out for a 13 mile test run and it did wonderful.  Excellent support and coverage and didn't chafe.  I did use a Glide stick as usual under the straps and such to prevent chaffing, but it did well none-the-less.

I like that you can adjust the straps and there was no bouncing.

One thing I didn't like is that only the outside is seamless.  The inside still has seams, which I don't like because the constant friction of running can cause irritation.  Also, the adjustable part of the straps is velcro, and the velcro fastens on the inside of the strap against the skin.  But, like I said, despite the seams there was no chaffing or irratation from my long run.

Highly recommended!