For a while there in the .5 to .8 days performance was pretty iffy, and the documentation was lacking (as was expected for a library pre-1.0), but it seemed that was when a lot of bloggers picked it up, compared it to react/angular, then dropped it.
And back then when I was trying it out there wasn't any easy way to integrate webpack (or something like it) which made it difficult as I've gotten very used to a good bundler/compiler.