it depends entirely on your criteria and the specific project. It's almost always more expensive, unless you are doing a large number of identical homes or a large project with repeating modules.

But - it is higher quality in finish and can be engineered to perform more efficiently. There are some very nice projects out there which use precast components.

The location of the project matters, since it costs money to transport the panels depending on the distance to the production plant. Also, you'll need crane access on the site, which may exclude certain remote locations.

It also requires a good contractor who understands pre-cast construction. This should be discussed with the client if they might have some ordinary home builder in mind.

you will be able to find a mason anywhere, readily available trade there won't be a lot of confusion or questions about how to get it done..

precast is expensive and has limited availability and knowledge base (structural consultants, CG, and subs)  depending on what market you are in.  Read:  specialized construction and detailing.  

Economy of scale and location are key factors.

Precast is one of those things that gets thrown around in the early stages of a project but gets quickly value engineered out once the project gets to nut cuttin time.