JSON is traditional: dictionaries, arrays. OO languages have built-in syntax to deal with those, via [] and dot notation, and the array objects nowadays have ways to do map() apply() grep() etc. on the collections.

The main thing missing is that XML has attributes, so you can query against those.

I won't say that the JS stuff is better, but it's one less thing to learn, and what you learn is directly applicable to writing apps in JS.