I think that to notice the difference with any of the super mags, you have to spend alot of time on the range and be very proficient with a rifle and its characteristics. When you are talking about ballistics of these rifles, you are talking about adequate big game guns to 1,000 yards in proficient hands. I don't think that you would notice much difference in one or the other if your shooting will be done any closer than 300 yards. If I were sixteen, I would get one of the .300 mags, or maybe a 7mmSTW, and go from there, because they are so much cheaper to shoot. Keep in mind also that a scope has to be able to handle the recoil of any magnum rifle, so you don't want to cheap out in that department. Between the two, I would probably opt for the Lazzeroni, given an unlimited budget, because he builds such amazing rifles and cartridges. You can't go wrong with a weatherby though either, and the 30-378 is a hot, hot round too. If you are set on a supermag, flip a coin, and get out the wallet. Good luck man.