Love it on my PC & iOS ... hate that it does run on my Mac!
Love eFax on my PC, could not without it, love it on my iOS devices ... BUT I HATE that I cannot enjoy that same functionality for my Mac OSX! Its a real PITA to send an eFax from my Mac, I have to save the document to my DropBox, open it up on my PC or virtual machine and the eFax it ... still searching for a desktop fax app that runs on PCs, Macs and iOS devices but there just arent any options.
BSabio about
eFax App–Send Fax from iPhone, v4.7.2