... and so far very impressed.
I auditioned them firstly with a Marantz PM6004 (the nearest thing to my amp), then with an Onkyo A3000R (which I also eventually bought). I'd say the speakers took around 50 hours to settle down. I have them set up about 50cm from the wall, away from the corners, and about 2.5m apart. They are toed-in slightly for a better stereo image. I spent a while experimenting with the angle of the toe-in as it seems quite sensitive. I sit around 2.5m from each speaker.
They are the first floorstanders I have owned. They are quite slim, so do not take up a great deal amount of room. The finish is excellent - I went for the gloss black. The speaker terminals can be a bit fiddly with the jumper bar (I'm not using banana plugs, just bare wire). I intend to get some jumper wires with spade ends, and fit plugs to my speaker cables... at some point. Out of the box, you need to fit the glass plate which forms the 2 rear feet of the stand. The supplied instructions are very clear, and the required hexagon wrench is supplied. They are solid and fairly hefty so watch your back when lifting!
My first impression was "Oh, this is what speakers are supposed to sound like". I have to admit I was previously running bookshelf speakers on the floor (Yes, I know. The shame!). I did try out some stands but with a small person running around the house, I got my Health & Safety head on and decided they were not stable enough. The Concept 40 stands are pretty stable on a flat, level floor.
They are senstive to placement: initially I had them too close to the wall and they were a touch on the boomy side. This may also have been a feature of the bedding-in process, can't be sure. I eventually settled on the optimum position and angle for my listening position.
They cope very well with the variety of music I throw at them. I'm no expert, but I like what I hear.