I'm just going to use the track record of communist dictatorships worldwide as evidence that where a traditional dictator kills a few thousand, communists kill a few million. Considering that the Republic had been thoroughly compromised by Stalin's agents and seeing what they did in their own territories in the brief time they had, I'm very confident that Franco was certainly the lesser evil. Much of the facts have been twisted out of all recognition as well. For example, wikipedia cites Anthony Beevor's numbers as conclusive, but his numbers are based on biased accounts.

This book, however, does not serve as an apology to Franco's regime. It only charts that antireligious violence started in 1931, well before the start of the civil war itself, and continued until 1939 when the Republic died like the dirty miserable shit it was (that last bit is mine; the book doesn't say that).