The Survivalist series heads to China as the race is on for a deadly stash of nukes that could end what little life is left on Earth five centuries after World War III. Overlord is Survivalist at its best; the threat is clear, the pacing fast, and our heroes overcome odds in the name of freedom (with the added bonus of a new faction). Ahern's writing can be a little shaky, but we're 15 books into this series and I've long been able to fully enjoy it for what it is.
Overlord itself won't disappoint fans; although there are more sci-fi elements introduced as characters develop psionic powers. That may turn some off, but pulp readers should find it a fairly familiar trope. Overall I'd give this a 3/5; and for post-apocalyptic pulp enthusiasts 4/5.