I've whitelisted a few sites I like to support (a couple of webcomics, HaD etc).
I have a lot of filters: "62,501 network filters + 40,728 cosmetic filters".
Opera's task manager says the extension is taking up a mere 32MB. Probably not accurate, but a lot better AdBlock (my previous favourite).
Off-topic but I wish people would stop using Mu for project names. Where is the Mu key on the keyboard? I have to copy and paste or alt-code it. Call the project microBlock or something! They use "u" instead of "µ" on Github, so why not just use something else entirely?
µTorrent was the one that really irritated me because I couldn't type "utorr" to search for it on my start menu.
I'd say something to gorhill (albeit far more politely), but it seems childish and ungrateful. He's clearly poured so much time and effort into making such useful software. "Great software but the name is fucking annoying, mate!"