I've tried the built-in fax feature in Panther, and every time was left wondering if it actually sent anything out... Page Sender is great -- It does everything I need, and there is never any guesswork. I actually enjoy using this program, which is probably the best thing you can say about an app.

The one time I had a problem (not sure if it was a Page Sender or OS issue), I had an answer via e-mail within 20 minutes -- and this was *not* during normal office hours! These people chose their company name ("SmileOnMyMac") well.