The 480 would have more "wow, that's cool" appeal at the range since by this time everybody has heard of if not shot a 454. If big blast and flash is what you're looking for then go with the 454 as Lenny suggests, higher pressure in the 454 will make a bigger bang.
Hottest data I've seen puts the 480 up into 454 Casull territory, a little less energy but more momentum and a bigger heavier bullet.
I haven't seen any 480 ammo for sale but I'm sure it will be EXPENSIVE. Some of the smaller custom ammo shops are selling it for $100 a box - yes, $2 a shot. The 454 will handle 45 Colts which can be found almost anywhere for $20 a box or less. If you handload either will work, if you don't I think you'll find it a lot easier to feed the 454.
If it were me and I was looking for a ego gun I'd go with the 480, it's newer, its more powerful (by some measures) it tosses really big bullets down range and it's developing a reputation for being extremely accurate - at least in the Rugers.