I think that anything that helps bring up property value is good for the community. I know that I would welcome a huge house that made my property go up in value. I don't know how others feel about the eye sore,but I like to look at what homes I can't have.
These homes are nothing but expensive mistakes in the development of suburban areas. They all look the same, and are going to eventually drop in value. I think this, in the long run, will have a detrimental effect to the neighborhoods in which they're built. I'd personally rather live in a cabin.
There is nothing beneficial about "mega homes" anywhere, which we usually refer to as McMansions. They are usually cheaply built and will not last for long. They are energy ineffecient as a result. Also, the construction of such homes is not environmentally friendly. And finally, let's not deny it, they're ugly as sin.
I do not believe the development of brand new "mega homes" in suburban communities is beneficial. I think these homes were more popular before the housing market crashed, but even then we saw people buying far too much house. More than they could ever conceivably need. However, this is the precedent in America, buy big and buy too much. This ideology is not good for this country, it is not good for economics in the long run, and it certainly is not good for the environment.