It's good in theory, but badly programmed:

On first installation, this extension (re)loads all open Twitter tabs and opens a new tab with a Twitter login prompt for each of them. If you have too many open, this will freeze your browser.

It also adds a button to the menu bar, but the developers didn't fill in the default empty popup when you click on it or gave it another function. That makes that symbol there completely useless.

The extension would be a lot more useful if it automatically checked tweets that stayed on screen for a second or so (to avoid polling everything when scrolling quickly). There's a JS API to do that with very low performance impact now.