TEOTWAKI was the first survival fiction I ever read back in like 1998 or something. Fond memories. The new books aren't as good, but I've gotten some enjoyment out of them.
I agree, the Holding Their Own series was good. The Desperate Times series by Nicholas Antinozzi was pretty good too. As far as Founders, it was OK, not really what I had hoped for.
I HATED the Desperate Times series. It was like a really bad soap opera with inaccurate gun info thrown in. The SF guy in particular was really badly written. Not because he's gay, but because of the incompetent tactics he displays.