As to the point to go ahead and just get a 12" jointer, they'll be someone who says you'll never be satisfied with a 12" jointer so go ahead and get a 20" jointer.
It becomes like someone who wants a bench-top drill press and someone says go ahead and get a used Bridgeport milling machine.
It seems to me the OP expressed that he had room and the money for a new 8" Grizzly. I'm not second-guessing him as he seems to know what he wants, has done the research, and doesn't appear to want a used jointer for whatever reason.
The Grizzly is a good jointer, at less money than other brand names and has great reviews from those that own or know about Grizzly jointers.
Of course everyone has an opinion, but the only one with the money in the discussion is the OP.
"If only those heathen atheists hadn't taken God, Jesus, and the Bible out of schools, God and Jesus could have thrown a Bible at the shooter."