The Secret of Warwick Village is an engrossing, compact setting. It packs a lot of information and flavor into its pages. In the past few years, I have started playing three different campaigns set in the Lost Mines of Phandelver. It seems like a lot of players want a sandbox experience, but a lot of DMs don’t know where to start. The Secret of Warwick Village is a good launching point for that sort of campaign. It is not necessarily a complete sandbox but a skeleton on which to build your own sandbox.
It starts with some creepy backstory which I won't ruin here, but is a nice twist to give the area some flavor. It does a succinct job of low level world building by giving many locations and npcs that have enough flavor to round them out, so a DM does not have to focus on world building minutiae and can focus on adventure creation and story development. There are hooks and interesting adventure locales contained within, but players can find these organically without having to be railroaded. It also brings a couple of interesting new monsters which pose a decent threat for first tier players.
For a short campaign book, it covers a lot of ground. It is a nice launchpad for a DM who wants to build up a campaign but not worry about the small stuff like what is the barmaid’s name, or what is her motivation. It also gives adventure hooks from which to give direction to write the next session.