Syndicated — In the simplest sense, developed land has been fully prepared for home building while undeveloped land has not. Each has advantages and disadvantages. If you're thinking about building your home on undeveloped land, be sure to consider the additional work and expenses.
Are We There Yet?
One of the most important things that a developer does with raw land is bring roads onto the site and connect those roads to the public right-of-way. Lots are usually located adjacent to the new road and have direct access to it. If the subdivision remains private, the homeowners will maintain the roads but often they're deeded to the city and maintained by the municipal service department.
Vehicular access to undeveloped land can be more difficult, although isolation might be one of your primary goals in choosing a rural location. You'll almost certainly spend much more to build an access road back into the site (I can recall several "driveways" that are more than one-third of a mile long) and you won't have city snowplows to clear it for you.
Red Tape and Green Paper
Buying a lot in a subdivision means buying into additional layers of government regulation including building departments and homeowner associations. Both groups will have a say about the size, location, design, types of exterior finishes, and maintenance of your house. Municipal building departments usually hold builders to a higher standard of construction quality than rural departments - a definite benefit to the homeowner - but that can mean higher construction costs, too. Subdivisions also usually have minimum house size requirements, so your home might even end up being larger than you want.
On a rural property you'll have much greater freedom to decide what your home looks like, what it's made of, and how it's arranged on the land. And with that design freedom comes more control over the costs of construction. Because the options are far less limited, undeveloped land is where most truly unique custom home designs are built.