.44 vs .45ACP
To me, the main difference is that you can buy .45ACP just about anywhere, even Walmart. But finding .44 SPL is a LOT HARDER. Also, in factory loadings, the .45ACP has a LOT of options in loading 185-230 grain, FMJ, hollowpoints, etc. .44 SPL, if you can find them , are usually only found in cowboy loads, at least around here.
If you load your own, that narrows things somewhat. It's a personal choice that has more to do with the shooter than it does with the caliber . For me, since I shoot a 1911 as well as .45ACP wheelguns, I will stick with the ACP> That's MY CHOICE, everybody else has to do the same for themselves