All neopanel based speakers will have a similar sound. The tweeters, and woofers will adjust that sound accordingly.
More panels will allow a speaker to play louder with less stress. Larger woofers will of course give you deeper and more dynamic bass.
There will also be a small difference relative to a cabinets "shape". The RM30, RM2, and RM v60 will all have a slightly different sonic signature due to some cabinet and baffle differences.
The Neopanel based speakers will also sound different than the cone driver speakers of the past. They will have slightly more detail, resolution, microdynamics, and presense.
The Cone drivers will have greater macrodynamics.