I live in a mobile home. It was more affordable than a traditional house. Which is a good point to consider these days. Mobile are good as long as you don't live in Tornado Alley. Getting a loan for a MH is different from a loan for a traditional home. And Mama Kaz is right, MH are appraised just like traditional. I pay my fair share of property taxes. I feel very safe and sound in my MH.
Modular homes are actually appraised the same as conventional homes. You are right about mobile homes though. I recently found out that modular homes (and mobile homes)have much tighter government construction regulations than conventional homes because they have to be designed to roll down the road at 60mph. You can definitely get more house for the money with modular and can order your house and have it delivered in as little as 6 weeks.
I'd have to go with conventional home, because you KNOW the value on the mobile will probably drop. Plus with the suppression of home prices you could get a nice house cheaper if you got the money.