i spent enough years dragging 80,000 lb trucks up and down the mountains west of denver that my manual shifting jones has been completely satisfied, thankyewverymuch. if i never shift another gear in my lifetime that is just fine with me.
unless i'm driving my 911 of course, which naturally has a manual gearbox. if my wallet was sufficiently inflated to the point where i could think about buying a newer porsche, i'd get one with a pdk. the pdk is porsche's dual clutch gearbox and is supposedly the absolute bomb. no chance of that, so i'll keep the rather balky 915 gearbox.
as for tractors, my thinking goes along the lines of shuttle > hydro > manual. i foresee a about a 50% ratio of of loader work and pulling various tph implements, and a shuttle would seem to be the best of both worlds.