I like the original CLS's the best. They had the most magic IMHO, but they were also not as capable as the later versions. By "capable" I mean the later versions extended further in frequency response on both ends, were less picky about amplifiers, and had little bigger sweet spot. (well, even a couple of inches is a little bigger than the original version I had).
The pristine clarity and spooky realism of the original CLS's midrange lost something with the latter versions, IMO. One note of caution about the original CLS's though - their panels probably need replacement by now, or should have been replaced already. From what I know (don't quote me on this), the earliest versions essentially wore out after a few years. But by then, ML had gotten the problem solved, so the replacements should be set for a very long time. This part I know from first hand experience.
The pristine clarity and spooky realism of the original CLS's midrange lost something with the latter versions, IMO. One note of caution about the original CLS's though - their panels probably need replacement by now, or should have been replaced already. From what I know (don't quote me on this), the earliest versions essentially wore out after a few years. But by then, ML had gotten the problem solved, so the replacements should be set for a very long time. This part I know from first hand experience.