As other people have said, slows your whole computer down. however, it is open source, so it's not like they are doing anything sketchy.
Oh and the main problem is that it doesn't work. Even with the same tab redirect prevention on (5th page of extension settings) it still redirects me to another site.

Высокая нагрузка на просессор

Las redirecciones las bloquea pero (como ya han reportado otros usuarios) consume una cantidad enorme de CPU constantemente. No la instales.

Trash, do nothing. wasted time.

Stay away from this extension. As others have said it has an insane amount of cpu usage. As high as 44% for me. Could be some nefarious things going on in the background so best to just avoid. Considering the fact I had this also installed on ungoogled chromium and it didn't do all that this might be a rip off of the official extension on the chrome web store. Either that or it's broken or abandoned on mozilla.

it spike my CPU ...suspicious , behavior similar to CPU miner

Doesn't work. Crashed my browser.

Suspicious high CPU usage, fans spinning at high rpm ... while everything is idle with no tab open.

Works, except by the extremely high resource usage, the CPU and RAM usage is ridiculous

This is impossible to adjust, it blocks and lets through as it pleases. I don't think it can work any worse.

technically great but for some reason it takes up all ram

Literally used an entire 8gbs on my pc to do, what I assume is, bitcoin mining or something.

Did not block redirects.