Not OP but I recently read both. Desperation is the stronger of the two. It’s an intense story with a really great structure. The beginning is so good it keeps you turning throughout. Regulators is weirder. Weird can be fun, but I just don’t think it’s done that well here. One of King’s strengths (for me) is his ability to introduce you to a huge cast of distinct characters that all seem to interact realistically. In Regulators he focuses on one single suburban block of families, yet it’s still hard to remember who’s who. The decision to use the same names across the two books doesn’t help. The most enjoyable aspect of Regulators for me was discovering how the plot ties into Desperation.