Billygoat for no other reason than you can adjust the chute from the handlebar on the move. At LEAST 8hp thou 10 is better, I have the 10hp.
Run it for 8 hours, change the oil to a standard oil, run it for the season then switch to a synthetic-base 10w-30 to 10-40 weight and she runs like a champ.
Only problem I ever had was a blown head gasket in 3 years of heavy fall-time use... don't do leaf cleanups in spring no more.