I'm a bit biased, as I publish PDFs and also do some work for RPGNow, but there is something I wanted to add:
In my opinion, the PDF market right now reminds me of period in the mid 80s when there were a wide variety of gaming magazines (Dragon, Pyramid, early White Dwarf, Different Worlds, etc.), all of which offered tons of usable gaming material. The way I see it, PDFs work best when they fill that role--usable gaming material that a consumer can purchase "a la carte."
In my opinion, the PDF market right now reminds me of period in the mid 80s when there were a wide variety of gaming magazines (Dragon, Pyramid, early White Dwarf, Different Worlds, etc.), all of which offered tons of usable gaming material. The way I see it, PDFs work best when they fill that role--usable gaming material that a consumer can purchase "a la carte."