Ive been doing some serious research into them as well. In my experience, what I have seen work best is to either build a hut for it, or I have seen folks dig a pit for them, and that seems to work even better. A tarp covering 3/4 of the pit and the noise is literally gone. I assume the same could be said for a hut.
As for models, Im looking at a Generac, but I am also looking at a home generator hooked into the NG line that wont be portable in any way.
Hope this helps.