Most recent update has caused numerous websites to no longer correctly function for me. I don't know if this is the same for other users, nor the extent of what sites are affected.
Youtube does not load video pages on left click, it requires a "New window" or "refresh page" to play a video you click on. Mild nuisance.
Bigger problem: Email is failing to load and I must disable/re-enable uBlock to view anything. Probably other problems. If this were my first impression of your extension, I would judge it very harshly. Only because I have had very good experiences do I not feel this way now.

best blocker ever!

Ublock is amazing. I haven't seen an ad in so long! It makes my whole experience safer. It's quite simple to customise (I've never used the advanced settings though as I am definitely not an advanced user). I appreciate this extension and the people who make the filter lists so much.

Haven't seen an ad, or a website detecting I have an adblocker. The only thing I've seen is a website saying "an ad used to be here", but those might've just been placed behind the ad and not a sign of the adblocker being detected.
Youtube does sometimes detect you have an adblocker, but it's always fixed within a week. Even then, them purposely making your video load 5 seconds slower is less annoying than a 30 second ad.

Ótima extensão.