There is some overlap in what Saft and Glims do, but they are essentially different programs. Among other things, Saft provides a granular method for blocking ads that Glims does not. But in years of using Saft I never dug into this feature to learn how to use it. I mostly used Saft to control tab behavior and, in particular, to automatically reopen all windows and tabs from my last session in Safari. Without this feature I had to remember to go to the History menu every time I launched Safari and select Reopen All Windows from Last Session. If I forgot to do so, all my windows and tabs were lost. Glims offers many of the same tab control features and more. And, unlike Saft, Glims does not require an update every time Safari is updated - though we did have to wait a few weeks for Snow Leopard support. In which time I paid for a Saft upgrade because I didn't know whether Glims would make it to Snow Leopard or not. I wish the developers had been thoughtful enough to let us know on their web site that a 10.6 fix was in the works - it would have saved me the $15 I spent on the Saft upgrade - which I now cannot afford to donate to the Glims project.

Another casualty of the changed environment in Snow Leopard is Pith Helmet, which I have used for a long time and found to be a most effective ad blocker. In it's place there is Glimmer Blocker, which does not hack Safari in order to block ads and hence does not suffer every time Safari changes. Also useful - and upgraded for OS X 10.6 - is ClickToFlash, which provides invaluable control over those annoying flash ads that clutter so many web sites now.

In sum, I use Glims because it doesn't break every time Apple updates Safari, which they seem to do on a monthly basis these days. Also, Glims has surpassed Saft in tab and window control, and I like some of the unique features it offers. That's not to say that Saft is defective in any way, and the author has found a way around the limitations Snow Leopard imposed on its previous method of operation. But I prefer Glims now - and it is freeware.