Comment by hnedeotes

Not to piss on your experience, I use WebComponents for almost everything and they have a lot of issues (mostly they're not really integrated into a coherent model with the remaining things that always exist in their presence, the browser, DOM, lifecycles, requests, etc) but being slow can only be an issue of your implementation to be honest, it's an imperative model for the most part - in fact the reason why I've started using them was because it was much easier to make things fast easily - there's no way updating/replacing dom elements surgically is faster with any other framework.