Curious as well. I have a 2014, but was updated by Friedman with the JBE MV--I'm the second owner, so not sure when that was done and if anything else was upgraded; I'd have to check with Dave and the Serial Number.
Regardless, if you can find one with the MV, go that route, especially if you gig. If not, it's not necessary, unless you want a '3 channel amp' at the footswitch.
I have the 100w with the JBE MV: for what I do at gigs I need it. I’m tempted to sell my JJ100 now and fo for the Jr, but there is no way the 20 matches the 100 in feel at those larger stage volumes. But I will give it to you, and I’ve not played the 20w, that the Jr/20w can deliver the JJ100 “sound and feel” at lower gig levels. I’m not sold on the DI to PA tones I’ve head online yet, which I would need for my small to medium stage gigs, but overall, I’ve seen more JJ100’s up for sale in the last year or so.
Still love my JJ100! Prolly can’t go wrong with either!