OK, I'm a bit behind in catching up with this thread! I was really surprised when I read your comment, Jaime, because it seemed to me that I have been in the minority in thinking that RD is Evergrey's weakest effort. Not that I don't like it, I do--I just don't think it's as inspired as their other releases. I was pleased when I heard TIC because I felt it was a step in a stronger direction for them, IMO.
I started listening to Evergrey after the first ProgPower USA, so before ISoT came out. But ISoT is definitely at the top for me, followed closely by SDT. Although the way things are going, TIC may be up there pretty soon! RD is at the bottom of my personal list, but it has grown on me more over the past few months--The Great Deceiver, End of Your Days, I'm Sorry, and Blinded are my favorites (still don't much care for the title track--not quite sure why).
I really think it's a personal thing, whatever speaks to you more strongly. I don't think one is necessarily "better"--they just appeal to people in different ways.
Lorraine