Here's a humorous post (End the Fax Tyranny) with a bit of a rant about the challenges of faxing - traditional faxing, that is. To summarize (without the humor): it's expensive; a waste of space and paper; and they are a pain in the ass to send. (You should read the funnier version here.)
Internet fax services like MyFax are cheaper, paperless and as easy to use as email. If you never need to communicate with a fax machine then MyFax isn't for you; but otherwise - it's a lot cheaper and easier.