I’ve not got a lot to add here, given the fame of this site and its comprehensive coverage in all sorts of guide books. A great little volume written by the O’Kellys is available from the proud and committed landowner.
Aubrey Burl in his big ‘Stone Circles of...’ book remarks that the monument’s relationships lie with the Wicklow circles and not with the Scottish recumbent and Munster axial stone varieties. I’m not so sure that a connection to the ASCs should be written off completely. Two northeastern portals look along a main axis, with a winter sunset declination, to two stones at the southwest which, because they sit together, give the same shape as one more broad than high. A supplied v-notch sits in the middle of these ‘axial stones’, an effect also offered by natural valleys in the sightlines of the Winter Solstice circles of Drombeg and Lettergorman South. Maybe in 1000 years an idea could mutate and fuse with other influences and appear some distance to the South?