@amit Yeah, like @smokey guessed, both lag and jitter are recurring issues for the Samsung Chromebook Plus that I'm using. It's mostly when you've got Android apps running that both websites and Android apps become jittery/laggy.
ChromeOS can be buttery smooth but IME you have to avoid Android apps to keep it that way. Someties just launching and then exiting an Android app is enough to make the entire system jittery. I'm guessing having the Android subsystem running in the background is enough.
An especially annoying issue is Youtube playback lag/stutter that sometimes comes out of nowhere.
I've also occasionally gotten a bad update that introduces lag/jitter which then disappears in the next update (and this is on stable btw).
I think a lot of people just don't see jitter or lag even though it's there. They're so used to UIs being unresponsive that they are blind to it. Which is my theory as to why the online ChromeOS community doesn't talk about the issue that much.
I think ChromeOS is a great concept and maybe it'll get there eventually. But it definitely isn't there yet.