I've used both stacks for years. I have no complaints about Maven, to be honest, it just works and I don't really spend much time thinking about it as a result. On the other hand that's been less true for npm, hence why I've now switched over to yarn.

Maybe I'm missing something though - 100x is a bold assertion and I guess you must have some very strong reasons for preferring npm's features over Maven to warrant that - would you mind explaining a bit more?