If you are building something for wide market use then definitively don't use these new features until they are supported by multiple vendors. But before standardization can happen things have to be tried out, I don't see what all the negativity is about when it comes to new features in chrome (I don't get the same vibe with Firefox only features).

It's better, in my opinion, to have a working prototype of a feature working and used by some early adopters than to build standards in a vacum.

Those early adopters need to know those features my disappear or the apis change and be ready to fix their code.