They are using a slightly bigger magnet than the floorstanding concept 500 from what ive read. It is basically a similar design to the floorstander except in a smaller package for people that dont want a big heavy floorstander. The floorstanding concept 500 are well regarded.
I have heard the concept 300. Based on the brief demo in the store i was impressed by what i heard. They are pretty good.
I have also heard B&w 805d3 and Kef reference 1. These were definitely not as good as the q acoustics despite being more expensive but it was a different room so comparisons are not completely valid.
Its worth listening to. I have nothing against ATC but the scm11 i heard were not that impressive, again taking into account the acoustics of the demo room.