Most of my referrals come from factory built home dealer/builders. These homes are great for the FHA construction loan program, they save on construction costs and time. They are built with quality materials, in a controlled climate, to very tight specs.
The first question I always have when speaking to a new client that is buying a factory built home, "is it a modular or manufactured home"? The most common response is silence or "I don't know". So let's take a moment to go over the differance.
Manufactured homes are built to the Federal building code, which is also referred to as the HUD building code. These homes typically come out of the factory in one section, also know as a "single wide" (which are not eligible for the FHA construction loan) or two sections, aka a "Doublewide" (which are eligible).
Manufactured homes will have a 1" x 3" red HUD code tag on the lower, right hand of the exterior of each section and a metal undercarriage. They can be placed in "parks" where the land will be rented or on a permanent foundation on land that you own. The ownership of the home is documented with a title similar to an automobile title. If the home is place on land that you own you have to go through the process of "retiring" the title with the state government.
Manufactured homes typically are built in a ranch style, have a lower roof pitch, and lower ceilings. If they are built on a basement you should be able to see the metal undercarriage that supports the floor. These homes are shipped from the factory by putting axles and wheels in the metal undercarriage.
Modular homes are built to the state building code, just like stick or site built homes. They can have any number of sections and can be built to any style. Since these homes are rarely, if ever, placed in a park, they don't have an automobile type title. They are shipped from the factory on a flatbed truck and craned on to the foundation.
As a practical matter I greatly prefer to use the FHA construction loan program on Modular homes. The appraisals are easier since site built home sale comps can be used. On a Manufactured home the appraiser must be able to find other manufactured home sales, in the area, in the last 6 months. This is difficult in most areas and impossible in others.
Modular homes will cost a little more but it's my experience they will hold up better through the years. If you can afford it, get a Modular home.
For more information check out these articles at Wikipedia;