Purchased PageSender 4.0 to overcome some issues with the fax program in OS X (10.4.9). The MAC was not always answering the ring/picking up/receiving faxes consistently.
Given that receiving faxes (from the few left that send them) is critical to my business, I decided to upgrade to PageSender. Since I deal almost exclusivel with *.pdf's for fax mode (either send or receive), I have not experienced the issues noted in other reviews. So far, the program is doing what I need and as long as it doesn't miss inbound faxes I'm satisfied (maybe that's a low bar, but it is what it is). As I use the program more frequently, I'll update my review.