The XBA-A3 is kind of a bass cannon compared to the A3. For some reason, I still find the A3 enjoyable, despite it having way more bass than what I normally like. However, because of its big bass boost, there seems to be a bit of a slight veil over everything, compared to the 2000J. The mids are less forward except for the lower mids and the uppermost upper mids. The bass is richly textured, but is not nearly as revealing, coming off a bit one-note compared to the layered and nuanced bass of the 2000J.
Honestly, there should still be people who like the XBA-A3, as well as the warm, sweet, smooth-ish 2000. But there's no question the 2000J has better clarity, better bass control, better treble extension, and better detail. It's mostly down to preference.
People who don't like hearing any treble harshness will go for the 2000. People who want to hear big thick fun bass, will go for the A3. People who want control and resolution will love the 2000J.