Funny you should ask this as tomorrow I am meeting a fellow basschatter to exchange my 2004 olympic white CIJ mustang bass for his black JMJ, both basses being in the same ballpark value wise.
The CIJ was my first mustang and in a previous band was my go-to gigging instrument. Back then I always said that I'd never sell it, but I always wanted a daphne blue one. When the JMJs first appeared in daphne blue I bought one despite not really being into the finish being roadworn, however I grew to appreciate that as I can gig the bass without worrying about it picking up dings on the body. I now own two blue ones and after tomorrows meetup I'll also own two black ones. The JMJs have been my rehearsing and gigging basses for several years.
The MIJ/CIJ mustang necks have a thicker glossy poly finish and a skinny profile like a Jazz bass, but the thin nitro finish on the JMJ necks is more satin/almost matt with the profile more like a nice precision. As I got used to the JMJs I played the CIJ less as I preferred the feel and chunkier neck profile of the JMJs.
I also have a couple of 72 musicmasters — the secret to getting these to sound great is to fit a Kent Armstrong cool rails strat humbucker pickup like this one: https://www.armstrongmusic.co.uk/products/mini-humbucker-power-blades-cool-enclosed-cover