Plagiarised is totally the wrong word here. Besides, We is satirical so quite different in tone. I greatly enjoyed all three novels though, and encourage people to read them all :)
It's almost the exact same plot as 1984 in a different sci-fi setting. But yeah sure, pedantically speaking it's not exactly plagiarism but it's not exactly original either.
Meaning that Zamyatin got it wrong, too?
Yeah, We is actually pretty bad.
The question isn't which is better or more original, the question is which predicted the future better. If you say neither because they copied We, it stands to reason that We didn't get it right either, nothing about good or bad. There's plenty of great SF with terrible "predictions" and vice versa.