Looking at some of these lists, it's interesting to me how varied the "groupings" are. It's kind of well-accepted that Rush has "eras":
Rush - 2112
AFTK - MP
S - HYF
P-TFE
VT-CA
Some people have a mix, some people have clumps. Neither is a right answer, but it's interesting to me. I think there's an arc to their career; there are no HUGE jumps from album to album, but certainly, comparing "CoS" and, say, "RtB", the differences are stark. I would argue that the only constant is Neil Peart's drumming and Geddy's bass; Neil's lyrical approach is different across the various eras, Geddy's singing is different across the various eras, the keyboards are different across the various eras, the guitars are different across the various eras, the songwriting is different across the various eras...
What a fascinating band, from this perspective.