HI!
In your opinion, which is better between the uBlockOringin and AdGuard browser extension in terms of filtering, privacy, performance and reliability? 
I don’t believe there is a direct comparison between the two on this system I don’t use ‘any’ Ad Blocker specifically, I did in the past use AdBlock.
uBlockOrigin isn’t specifically an AdBlocker, it does more than that, but it crosses over into that area. See attached screenshot/s
My main blocker is uMatrix and that also has a crossover as far as Ads go.