I remove Ad-Block on a case by case basis; if the site is one which I love, like Giant Bomb, I'll pay for the ability to remove ads and support it. Even if I love a site though I'm not going to turn Ad-Blocker off if they have awful advertisement polices (Pop-ups, audio advertisements and the like), that's something they need to correct and not the visitors responsibility.
Nah, you're right, Normal wasn't too bad. I wiped on the alien base invasion but after that I didn't have much trouble. Classic on the other hand, I've probably failed at least 10 times and restated. God damn it.