It should gather more signal.
But more importantly, it should have a narrower beam width, so as to reject adjacent satellite interference.
That's the main purpose of bigger dishes, in our application.
And if you're looking at the 8' Fortec, also give the
8' GeoSat a peek, as well.
I've considered getting one this summer, but am still dragging my feet.
Think there is a review of it
here on the forum somewhere (maybe in the review section?)
. . . and here is a
longer review.
I recall reading it a couple of years ago, and was favorably impressed.
So much so, that if they'd had a 6' version, I'd have probably gotten it then.
With any of these larger dishes, watch out for shipping.
It's a major portion of the price.
I'm located quite near the Port of Los Angeles, and am still trying to figure out how to pick one up from the docks or the closest warehouse.
edit: I see ACradio beat me to the answer while I was composing and looking up links.
He's a man with several 8' dishes; you should visit his link and see the hardware.