I do consider them as one to compare against others, simply because it was all released as one.
But I can separate them easily. My vote goes to Lemuria, it simply follows a more dangerous, braver musical path. I loved hearing Chris sing again, I loved a bit of a return to the "edge" that IMHO was somehow lost after Theli. I love also that it is so multi-dimensional, incorporating the beautiful title track to contrast with the darker tunes.
Sirius B is great, there are fantastic songs within, but on its own it cannot quite compete with SotR, Theli or Deggial.
Lemuria however I believe competes in its own right, it has its own unique flavour which lifts it up high alongside SotR, T & D.
...add together Lemuria and Sirius B, consider them as one - and now you see why I think they are invincible!!
PS That's a cool avatar Carlios! If I had to vote to choose best Avatar I'd be stuck between that of Manolo and that of Carlios. I could not choose...