It is very useful. I really like the way to scroll using j and k key (I personally map lowercase j and k to scroll half-page, which is very helpful)!
But I would say the most helpful feature is the link hints, which allows me to open links with keystrokes instead of mouse click.

Russian:
Очень понравилось, что прокрутка клавишами j, k происходит без задержки (при включенной плавной прокрутке). Также приятно, что можно гибко настраивать список игнорируемых сочетаний для каждого сайта.

English:
It's a pleasure to scroll the screen by j and k keys without delaying (if smooth scrolling is enabled). Also very useful is the ability to configure the ignore list of key bindings for each site.

it is like a dream come true

This extension is great. I have been using this extension for chrome. Now I can use it in Firefox too! Great!

Thank you for this addon - a very good alternative to VimFX! Is it possible to donate to you via Paypal?

Отличный плагин, когда руки устают от мышки!