The extension works flawlessly and adds button to collapse Hacker News comments. If you visit ycombinator news site, then you should give it a try.
It helped me in transitioning from Chrome to Firefox. Chrome indeed has several extensions that improve your experience at Hacker News. At the time of this writing, Firefox has only one extension, HN Utility Suite, that, offers collapsible comments at HN.
Rahul, you have titled this extension as "Suite". Do you plan to add more features to it? If so, please consider adding keyboard navigation support and custom CSS files.
Thanks for the kind words. Yes, I did intend it to be more than just comment collapsing, but in true HN style, wanted to release just a minimum viable add-on. I'll definitely look at adding keyboard shortcuts and custom CSS.