Any Experience Building a Modular Home?

I have a client who is thinking about purchasing a parcel of land here in Massachusetts to build a house on. These clients have asked me to help educate them on the prospect of building a modular home. I have not been through this process before so I would appreciate any comments, reviews and/or recommendations about the process...what to expect...what to look out for etc.

Feel free to contact me offline at judyboyle1@verizon.net if you'd prefer but I am most interested to learn more about the process, the industry, and the companies that assemble these manufactured homes. Thank you!