I'm not so much interested in blocking ads as I am in blocking popups. I know that 99.9% of all popups are going to be coming from those ads

The problem is that a 100-percent solution to blocking all popups will also kill some popup windows that you don't want to have killed. There are certain sites that use popup windows legally and they are necessary for proper operation of the site. Which is why I like the way AdShield handles it. It kills most of the popups and lets me hand-edit its kill list, but the "good" popups don't get blocked.

I was using a 100-percent popup blocker that let you hold down CTRL to temporarily allow popups. It had nice features, but it was unstable and kept locking up my browser. So far, AdShield has been a lot more stable for me.