I've been using PithHelmet for years, even sticking with it when newer versions of Safari would make it stop working. The bottom line is that it gets rid of ads. The problem, though is that noticeable delay that PithHelmet causes. When browsing to a new page or opening a new page, there is a delay of several tenths of a second. This would not normally be something that I would notice, except when using Safari's new "Top Sites" feature. It seems that the delay is additive in Top Sites, and the delay would cause Safari to stall for several seconds to tens of seconds, which is totally unacceptable. As an experiment, I ditched PithHelmet, and now new sites display instantly, including Top Sites. For now, I'm using a different free ad blocker, and it seems to be running flawlessly with no delays.