My above list above is based on my personal observations (listening), a dealer and custom installer, and Krell themselves as I have a great relationship with one of their major employees.
I have never heard before that the KRC2 was NOT at the bottom of the list. The reason some feel that the KRC3 is at the top of that list is that it has many advances that are actually used in the KCT.
To me, the the KRC sounded the same as my old KBL, but with remote capabilities. The KRC-HR was a definite improvement, primarily in transparency. I ended up getting the HR.
I could not afford the KCT and since my system is actively biamped, I cannot use the cast technology between preamp and amp. My dealer friend did upgrade his personal system to the KCT, but felt that the HR was more exciting, and he was ambivalent about whether he made the best choice.