With due respect to Mr.Rawles I really think that downloading a copy is not really the best way to go. The download looks to be one of the earlier versions and most likely lacks the last few chapters and some of the later tweaking that got done in later versions. I also think that buying the book has advantages.

To start with Rawles wrote it and, as much as I think it isn't high literature and isn't much of a survival guide, it is not entirely without value as survivalist fiction. It is something of a touchstone within the community and a valuable window into what the thinking was in Survivalism of the late 70s. Survivalism that hasn't changed that much over thirty years and which remains the evil stalking twin of preparedness and practical survival.

Burt Gummer in "Tremors" was a kinder, gentler version of that sort of bunker survivalism. "Patriots" fills in more of the dark, resentment and conspiracy filled corners of the genre but fails to climb the heights. It is IMHO just needlessly violence centered enough to be annoying and just gear focused enough to miss the point. Fun casual reading but to get the full flavor of gratuitous violence and gear fetishism look up Jerry Ahern and his "Survivalist" series. Plenty of material there, twenty-seven books of it. By the time you get through the first few books the need to read the rest diminishes.

http://en.wikipedia.org/wiki/The_Survivalist
Check the link for names of other writers in the genre and a useful guide to the "Survivalist" series.

In terms of buying versus downloading I also think that authors deserve to be paid for their efforts. Buying it from Rawles, or a vendor, gets you a hard copy book you can comfortably read in bed, keep on your bookshelf and loan out to friends. The actual cost of the book, including S&H, isn't much more than what you would send in paper, ink, wear and tear on your printer if you download and print it out.