Absolutely! I've never been kicked by a mule, but I'm pretty sure it's worse than shooting a .45-70...and I suspect that many people who compare the two have never experienced either.
The .45-70 is, I believe, the only cartridge that many reloading manuals have three separate listings for, depending upon the rifle strength and the shooter's tastes and uses. I've reloaded it with bullets as light as 250gr and as heavy as 500gr, and bullets can be had that exceed those limits at both the high and low ends. These are rifle bullets well suited to hunting.
The single .444 I once owned was pretty much a .44 magnum magnum; I don't recall if there were bullets designed for that cartridge or if they were are all handgun projectiles. They sure didn't range up as high in weight as the .45 slugs but maybe that's changed now. I doubt that there are as wide a range of projectile weights even today, but maybe someone could expand on that?
Is the Bushmaster using .450-diameter (i.e. handgun) bullets, or are they "proper" .458-diameter rifle slugs? If the former, then again, the range of bullet weights won't be as wide, and I really tend to doubt that the selection will be either. Again, somebody with experience with the cartridge (I have none) might clarify here. And in any case...does anybody even make a levergun in .450Bushmaster?
So if you are a complete beginner who intends to do no reloading, and have no preconceptions about what you prefer, the .30-30 is cheaper and likely easier to find on shelves. But if you are an experienced shooter who is perhaps curious about two cartridges that you haven't tried yourself, or if you just like bigger bores punching bigger holes, or you value the versatility of such a wide range of bullet weights and velocities, or you think you may want the big bruiser loads for some dream hunt someday...the .45-70 has it in spades over the .30-30.