I vote Solo.
With 3 friends this year, but probably the last time unless I can find someone willing to go on scouting trips and get in shape. Love the camaraderie, but am tired of waiting on guys who believe they are physically fit until they try to hump a 30+ pound pack into a remote area. Tired of feeling overall responsible for success or failure too - makes a hunting trip feel like work.
Committed friends are tough to find when you are 40+ years old and everyone around you has a family, professional responsibilities, etc.