@hossainshahriar Sorry but this is something that only you can answer, as it is kinda personal.
It depends on if you prefer to use a more stable app or if you prefer to have access to new features first.
Facebook was quite slow on my Opera GX too, after scrolling for like 30 seconds it starts getting more and more slow. No problems on the other browsers. Problems like this usually are because of some extension, in my case it was because of the WOT (web of trust) extension.